Post on 10-Jun-2020
APPLICATIONS OF HIGH ENERGY DENSITY PERMANENT MAGNETS
European School on Magnetism,September 8-18th, Cluj Napoca
W. KappelR&D Institute for Electrical Engineering ICPE-Advanced Research
Splaiul Unirii 313, sector 3, Bucharest, Romania
Magnetic Materials
European School on Magnetism,September 8-18th, Cluj Napoca
hard/soft
How works a PM?
European School on Magnetism,September 8-18th, Cluj Napoca
min1 12 2
mextm
m m m m m m mextt
W BHdv
W B H V B H V W
∞−
=
= = − = −
∫final
mextm initial
W BHdv Fdl∞−
= =∫ ∫
The highest loading energy of a PM
European School on Magnetism,September 8-18th, Cluj Napoca
maxmin1max( ) ( )2 mtW B H V=
min( ) / 50 /tW mass J kg=
Example: for NdFeB-PM with
max
:Comparison car battery 12 / 60V Ah410 /elw J kg=
Permanent magnets
European School on Magnetism,September 8-18th, Cluj Napoca
High energy permanent magnets
European School on Magnetism,September 8-18th, Cluj Napoca
Working at high temperature
European School on Magnetism,September 8-18th, Cluj Napoca
Working temperature
European School on Magnetism,September 8-18th, Cluj Napoca
MFS 350 sintering 2000 1.06 215 Sm2Co17
MFS250sintering20000.93170SmCos
Ugimag250sintering24000.6480SmGdCo5
MFS[ 220 sintering 2800 1.11 240 NdFeB
GM150hot worked11201.37360NdFeB-MQIII
GM200densified16000,80112NdFeB-MQII
General Motors125bonded12000.6164NdFeB/MQI
Vacuumschmelze210 sintering 3260 1.00 190 NdFeB
Shin Etsu180sintering23871.17263NdFeB
Shin Etsu80 sintering 875 1.40 390 NdFeB
ProducerHighest working Temp. (°C)
Manufac-turing method
jHc(kA/m)
Br(T)
(BH)max(kJ/m3)
Permanent magnet
Properties of some Re-TM permanent magnets
Working at high temperatures
Linear approximation: max max( ) ( ) [1 ( )]o BH oBH BH T Tα= + −
Where: BH I Hα α α= + Two PM at Te: max1 max 2( ) ( )BH BH=
at 12
12 1 2
1e
BH BH
kTk α α
−∆ =
−, k12 = (BH)max1o /(BH)max2o
Exemple Alnico IUNDK8AA, 3max1( ) 100 /BH kJ m= , 1 0.04% /BH Kα = −
NdFeB 3max 2( ) 300 /BH kJ m= , 2 0.70% /BH Kα = −
=> 100oeT C∆ =
European School on Magnetism,September 8-18th, Cluj Napoca
Working at high temperatures
cI o rH Iµ >>Reversible losses if:
We define max : cI o rT H Iµ = max1
I H
kTkα α
−∆ =
−from which: /ro o cIok I Hµ=,
max
max
0 1/1 0
Hk Tk T
α→ ⇒ ∆ → −→ ⇒ ∆ →
If 1 2 max1 max 2/ 1k k T T> ⇒ ∆ ∆ < That means
For two PM having the same coercivity, the highest working temperature has the PM with the lower remanence (sintered /bonded)
European School on Magnetism,September 8-18th, Cluj Napoca
max 200 )T K⇒∆ =
1(1/ 0.005 200K K− =
PM worldwide
European School on Magnetism,September 8-18th, Cluj Napoca
+ - PRCo; * - NdFeB; # - Ferrite; o - Alnico
max( ) /BH ρ/Energy mass =
max/ cos ( ) / : cos /Energy t BH t kgρ=
PM worldwide
European School on Magnetism,September 8-18th, Cluj Napoca
Load line
European School on Magnetism,September 8-18th, Cluj Napoca
0,m m m mcircuit m
dlH l Hdl H lAµ−
+ = +Φ =∫ ∫1
ccircuit m
dlAµ−
=Λ∫ c permeanceΛ ≡
1 2/ /g mc m
g m
k A k ASl l
λ= = Λ Λ =
0 00
0 0
(1 ) 1Hm
m
B H M N N SH H NM Nµ
→+ − −= ⎯⎯⎯→− = −
−
Recoil line/minor histerezis loop
European School on Magnetism,September 8-18th, Cluj Napoca
N – demagnetization factor of the PM
Ideal Permanent magnet
European School on Magnetism,September 8-18th, Cluj Napoca
(main demagnetisation curve)1=recµ → )(0 rmm MHB += µ
An ideal permanent magnet :
no irreversibil losses until Hd= intrinseccoercivity!
rB
)4/()()( 02
max µrBBH =
European School on Magnetism,September 8-18th, Cluj Napoca
European School on Magnetism,September 8-18th, Cluj Napoca
European School on Magnetism,September 8-18th, Cluj Napoca
European School on Magnetism,September 8-18th, Cluj Napoca
SNG λλλ +=
European School on Magnetism,September 8-18th, Cluj Napoca
European School on Magnetism,September 8-18th, Cluj Napoca
European School on Magnetism,September 8-18th, Cluj Napoca
European School on Magnetism,September 8-18th, Cluj Napoca
European School on Magnetism,September 8-18th, Cluj Napoca
Ferrites at low temperatures
European School on Magnetism,September 8-18th, Cluj Napoca
If T→ - 40C, A→A2 on the load line
If Hd is applied, A→B at 20C resp. B1 at -40C
If Hd = 0, than B→A1resp B1→A3 along the corresponding recoil lines.
If , A1 is not restored because the induction (magnetisation) even become smaller at higher temperature
40 20T T−
→
PM Applications
European School on Magnetism,September 8-18th, Cluj Napoca
Applications
European School on Magnetism,September 8-18th, Cluj Napoca
Different types of magnetic materialsType of magn.material
SOFT MAGNETIC MATERIALS HARD MM Magn. memory
Magnetostriction material
Transport properties
Field of appl.
E-tron. Sensors EMC E-techn. E-techn. E-tron. IT Actua- tors
Sensors Sensors
TM-alloys
FeSi, Nano &am FeNi
Nano FeNi
Composites M+polymers
FeSi, FeNi, FeCo, Fe
AlNi- Co
FeCoZr Permalloy
RE-TM NdFeB SmCo
NdFeB SmCo
TbFeCo RE-Fe2
Ferrit. Manganites
Soft ferrites
Soft ferrites
Soft ferrites
Magn. liquids
Hexa- ferrites
Hexa- ferrites
Fe2O3,
CrO2
LaREMnO3
Thin
fil
ms
Allo
ys,
oxid
s
Met
all
&ox
id
syst
ems
CoC
rTM
-R
E/Co
Cr
RE-
TM
Ni
Multi- layers
M-mu. layers
Mu.-lay.+insulater
Metall &oxid systems
PtCo RE-TM,TM-TM’ TM/nonmag/ TM,TM/insul./ TM
Nano Am.(Co) Fe2O3 Comp.with exch. interaction
Magn. wires
TM=3d-transition metal,RE=rare earth,M=metal
Magnetizing & shapes
European School on Magnetism,September 8-18th, Cluj Napoca
Applications of high energy PMGenerating mag. fields
European School on Magnetism,September 8-18th, Cluj Napoca
Cladding magnets/effects
European School on Magnetism,September 8-18th, Cluj Napoca
PM ApplicationsGenerating mag. fields
European School on Magnetism,September 8-18th, Cluj Napoca
Hallbach (magic) cylinder
)/ln(/2
)/2sin(12 RR
NNBB r π
π=
M Coey, D. White, the Ind. Phys. Sept.1998
H. A. Leupold,Static Applications, Re-Fe PM, J.M. Coey, Clarondon Press, 1996
[ ]int 2 , 2B B B∈ −
Hallbach Cylinder
European School on Magnetism,September 8-18th, Cluj Napoca
Inside notch
Outside notch⎥⎦
⎤⎢⎣
⎡−= 6
1
))((1)0()(RxgeometryPBxB insideinside
⎯→← x2
x
x
x’
x’
PM ApplicationsMagnetic Field
European School on Magnetism,September 8-18th, Cluj Napoca
Applications: PM powder pressing tools for anisotropic PM, built
from ferromagnetic steels
(for a sphere, but for a cylinder,
!2/''int MH = )
dB/dT=0 with thermocompensating alloys
European School on Magnetism,September 8-18th, Cluj Napoca
TKTKmm SBBSSB +=
dTdB
SSdTdB
dTdB
S TKTK
mm +⋅=
( ) ( )( )ommom TTBTB −+= α1dB/dT = 0
( ) mommTK
TK TBSdT
dBS α=
ThermofluxdTdB
BSS
TK
mmomTK
α=
TKS2 2( )R rπ − =
dB/dT=0
European School on Magnetism,September 8-18th, Cluj Napoca
Kw-meter
2 /break AlM B ρ
0 , 0( 0 ( )(1 ( ))Al Al Al TT T T Tρ ρ α= + −
0, 0, 4% /Al T Cα = −
21 1
12x m
dHF B Vdx
=
Field Generator
European School on Magnetism,September 8-18th, Cluj Napoca
L← →
Holding magnets
European School on Magnetism,September 8-18th, Cluj Napoca
Holding magnets
European School on Magnetism,September 8-18th, Cluj Napoca
2
02LBF Aµ
=
1 /R = Λ
-Demagnetisation curve
European School on Magnetism,September 8-18th, Cluj Napoca
Φ −Θ
m m m g g s s g sB S B S B SΦ = = + = Φ +Φ
m m m g g g sH l H lΘ = = = Θ = Θ1
/m m m
mm m m m m m m
l ltg RS S B H
αλ
Θ= = = = =Φ Λ
intg s
extg s
R RR R
R R≡ =
+
optimal optimal
m mR= Φ
Bearings
European School on Magnetism,September 8-18th, Cluj Napoca
21 1
12x m
dHF B Vdx
=
Axial coupling
European School on Magnetism,September 8-18th, Cluj Napoca
max ( )geom mag magM f BH pV=
Multiple Radial Coupling
European School on Magnetism,September 8-18th, Cluj Napoca
2 3~ 10 10T n Nm−
Radial coupling
European School on Magnetism,September 8-18th, Cluj Napoca
2 2max LM B R L
Eddy current coupling
European School on Magnetism,September 8-18th, Cluj Napoca
Tahometer
2 2max /LM R B ρ
Hysterezis couplings
European School on Magnetism,September 8-18th, Cluj Napoca
~ hystM pV HdB∫
Loudspeaker
European School on Magnetism,September 8-18th, Cluj Napoca
1 1( )2g m m mW B H V
γσ=
Voice coil motors
European School on Magnetism,September 8-18th, Cluj Napoca
Voice coil motors
European School on Magnetism,September 8-18th, Cluj Napoca
Motors with Nonferrousrotors
European School on Magnetism,September 8-18th, Cluj Napoca
π
SEA/France
ICPE-1980
Watches
European School on Magnetism,September 8-18th, Cluj Napoca
Magnetic separators
European School on Magnetism,September 8-18th, Cluj Napoca
Actuators with PM
European School on Magnetism,September 8-18th, Cluj Napoca
High speed motors
European School on Magnetism,September 8-18th, Cluj Napoca
G. W. Jewell, 2002, UK
PM motors
European School on Magnetism,September 8-18th, Cluj Napoca
Double Stator Motor
Stepper Motor
Flux Directions
Radial Axial
250 kW Generator
European School on Magnetism,September 8-18th, Cluj Napoca
G. W. Jewell, 2002, UK
Very high temperature motors
European School on Magnetism,September 8-18th, Cluj Napoca
Micromagnets
European School on Magnetism,September 8-18th, Cluj Napoca
PM for e.m. watch
ICPE-1982
Magnetic orientation
European School on Magnetism,September 8-18th, Cluj Napoca
Magnetotacticbacteria
Magnetic navy compass
Measuring Equipement
European School on Magnetism,September 8-18th, Cluj Napoca
Magnetic recording
European School on Magnetism,September 8-18th, Cluj Napoca
Medical Applications
European School on Magnetism,September 8-18th, Cluj Napoca
Many thanks to
European School on Magnetism,September 8-18th, Cluj Napoca
Mihai Mihaescu
Mirela Codescu
Mircea Ignat
Eros Patroi
Iulian Iordache
European School on Magnetism,September 8-18th, Cluj Napoca
European School on Magnetism,September 8-18th, Cluj Napoca
European School on Magnetism,September 8-18th, Cluj Napoca