Advanced softmagnetic materials for electromagnetic compatibility … · 2011-08-17 · advanced...

advanced softmagnetic materials for electromagnetic compatibility - EMC

MAGNET-TECHNOLOGIEMAGNETEC

© MAGNETEC GmbH, Langenselbold www.magnetec.de 05/2002 Dr. Fe 1/35

Advanced softmagnetic materials for electromagnetic Advanced softmagnetic materials for electromagnetic compatibilitycompatibility –– EMCEMC




- EMC/EMI basics

- mains filters and current compensated chokes

- comparison: nano and ferrite cores

- production process of nanocrystalline cores

Content of presentation




electromagnetical compatibility (EMC)

can be described as a - required - state:

„ the ability of a device, to work satisfactory in its electromagnetical surrounding, without generating disturbing noise, which could be

unacceptable for other devices.“

(EMV-Richtlinie 89/336/EWG bzw. EMVG)

Currently, the global electromagnetical background noise level doubles every three years ! 1)

EMC basics: definition of EMC

1) Schaffner EMV AG




Steep dU/dt switching edges of mircroprocessors or powertransistors (IGBT) or pulsed currents drawn from the mainssupply line of switched mode power supplies (SMPS) are the main reason for the unwanted emsissions of discrete or continuous RF energy.Examples:- digital telecommunication equipment (ISDN, GSM)- electronical power supplies for lightening applications- any kind of voltage converter using SMPS technology- variable speed drives- white goods with microprocessors and variable speed drives

EMC basics: sources of RF noise emissions




Comparison: 50Hz vs. switched mode power supply

50-Hz-mains adaptor - no RF- noise level but huge & heavy

230V-mains~

rectifierBig 50 Hz-trafo

smootheningDC-output

230V-mains~

small 50 kHz-trafo

switch EMI-filter

rectifier smooth. DC-output

SMPS - EMI filter required, compact, light weight, highly efficient

+-

+-




50-Hz-technologyexample: adaptor

Ps = 6 VA (12V / 0,5A) m = 440g η = 38 %

SMPSexample: notebook Ps = 30VA (15V / 2A)

m = 220g η up to 95 %

SMPS technology: significant reduction of size and weight




RF sourceemissionradiation

radiated noise distribution

conducted noise distribution

RF drainimmunity

Radiationnoise current noise voltage

possible ways of distribution of RF noise

capacitive andinductive coupling

E-fieldH-field

Is

Us

EMC basics: scenario




asyn-chronous motor

variable speed drive (inverter) = source

~~~rectifier dc-link

control circuit

PWM inverter

DC DC~~e.g.

ISA

0

10

20

30

40

50

60

70

100 1000 10000 100000frequency [kHz]

Un

ois

e [

dB

µV

]

0

10

20

30

40

50

60

70

100 1000 10000 100000frequency [kHz]

Un

ois

e [

dB

µV

]

rf

variable voltage & frequency

EMC basics: inverter drive as rf-noise source




EMC basics: sources of RF noise emissions

typical voltage andharmonics in a variable speed drive (inverter) –used in many futurePowerNet systems. Thoseunwanted rf-signals are distributed over all connected wiring systems

fundamental wave 4 kHz

0 20 40 60 80 100 kHz [f]0 20 40 60 80 100 kHz [f]

t = 50µs/unitt = 50µs/unit

T = 250µsT = 250µs

harmonics




~am

ount

%

100

50

01 kHz 100 1 MHz 1GHz10 10010

frequency f

EMC basics: ways of distribution of RF noise

typical distribution of emitted energy as a function of frequency

radiated emission⇒ shielding

MW SW FMLW

conducted emission⇒ filter




1:100.000

1:10.000

1:1.000

30 MHz

100

80

60

40

frequency

Qua

siPe

ak v

olta

geU

[dB

µV

]

class A industrial

class B domestic

EMC basics: RF noise level limits

noise level-limits of EN 55011 (common mode, conducted, 50Ω-system)

150 kHz




EMC basics: measurement setup for RF noise

reference ground

test device artificalmains

test receiver

woodentable

all values in cm




EMC basics: real noise level spectrum (quasi-peak)

1 10 f [MHz]0,1

Us

[dB

µ V] 80

40

0

60

20

80

40

0

60

20

Us

[dB

µ V]

poor filtering, limits of EN55011, class Bare exceeded

appropriate filtering, limits of EN55011,class B are met




EMC basics: future trends and outlook

-Increasing number of unwanted RF-noise sourcesresulting in a continuous increase of background level- regulations will be getting more stringent- regulations will be defined in new - new regulations to come- new noise sources will come- contious increase of costs for filtering measures- global introduction of emc regulations




EMC basics: mains filter

240Vmains

loadCx1 Cx2

Cy2

Cy2

L

basic circuitry of a EMI mains filter

Cxn X-capacitor

Cyn Y-capacitor

L current compensated choke

R discharge resistor

L1

N R

Filter

PE




EMC basics: working principle of mains filters

EMI filters are commonly desinged as reflecting low-pass-filtersausgelegt, this means, they work according to the principle of rf-mismatch.Thus, a part of the high-frequency currents are ‚deviated‘ – the other part will be aborped – e.g. in form of core losses and other mechanisms.

Cx1 Cx1

Cy2

Cy2

Lstreu

Cx1 Cx2

Cy2

Cy2

LN

differential modenoisef < 500kHz

common modenoise

f > 500kHz

Propagation of noise currents

source of noise

noise drain

noise drain

source of noise




EMC basics: setup of attenuation level measurement

conforming test setup of attenuation level αe

1:1

50 Ω

measuring receiver(selective voltmeter)

test item (filter)

1:1

50 Ω

measuring generator(150kHz-30MHz)

U1 U2

αe= 20 log U1

2 U2

[dB]




working principle of a current compensated choke for attenuation of common mode RF noise

EMC basics: principle of common mode chokes

single phase version

three-phase version

load current

RF current

Hload = 0

HRF ≠ 0

load currentload current

RF currentRF current

Hload = 0Hload = 0

HRF ≠ 0HRF ≠ 0




main requirementsmain requirements on a EMCon a EMC filter chokefilter choke::

high impedance (f = 150 kHz to 30 MHz)

Z(f) = ωL(f) = 2πf L(f)

L(f) = AL n2 mit AL = µ0 µr(f) Afe/lf

EMC basics: choice of softmagnetic material

number of turns iron cross sectionpermeability !




Feldstärke H →

Indu

ktio

n B

→

Bs

Hc

Br

Hs

Characteristics of softnagnetic alloys: Hysteresis loop

Bs: saturation lux density (high!) Br: remanence (low!) Hc: coercitivity field strength (low!) Hs: saturation field strength (high!)




- 1987: patent for a completely new softmagnetic materialwith excellent properties by Yoshizawa, Oguma andYamauchi (Hitachi, Japan)alloy composition: Fe73Cu1Nb3Si16B7production process: rapid solidificationmaterial structure: nanocrystalline; i.e. grain size 15 nm

- 1992: markt launch by VACUUMSCHMELZE(VITROPERM®) and HITACHI Metals (FINEMET®)

- since 1995: introduction into several industrial applications of power electronics and telecommunication

- 1999: 3. Source : MAGNETEC (NANOPERM®)

History of nanocrystalline alloys




Comparison of materials

Alloy Permeabilityµ‘r (10 / 100kHz)

Saturation inductionBs [T] (25 / 100°C)

Curie-temp.Tc [°C]

max. workingtemp. Tmax [°C]

Ferrite 3E7 15.000 / 12.000 0,38 / 0,21 >130 95Ferrite T38 10.000 / 10.000 0,38 / 0,23 >130 95

NANOPERM 100.000 / 20.00080.000 / 28.000 1,2 / 1,18 600 120 (180)30.000 / 20.000

NANOPERM vs. Ferrit:NANOPERM vs. Ferrit:- permeability - up to a factor of 10 (!)

- saturation induction - factor 3 - working temperature range - up to 180°C

- disadvantage: price ~ factor 1,5 - 2 (functional value)

⇒ advanced, smaller and lighter components ⇐




-1,5

-1,0

-0,5

0

0,5

1,0

1,5

-1000 -500 0 500 1000 H [mA/cm]

B [T

]

Ferrite T 38 µ = 10.000

NANOPERM

f = 1 Hz

µ = 80.000 µ = 30.000

hysteresis loops, saturation field as a function of permeability level






permeability as a function of temperaturepermeability as a function of temperature

0

10.000

20.000

30.000

40.000

50.000

-30 20 70 120 170T [°C]

perm

eabi

liy @

10k

Hz/

3mA

/cm

180

NANOPERM

Ferrite

max. for Ferrite:

about 120°C

max. for Ferrite:

about 120°C





saturation flux density as a function of temperature Tsaturation flux density as a function of temperature T

0

0,2

0,4

0,6

0,8

1

1,2

1,4

0 100 200 300 400T [°C]

satu

rati

on in

du

ctio

n B

sat

[T]

NANOPERM

FerriteN67

T38

max. for Ferrite:

about 120°C

max. for Ferrite:

about 120°C





typical impedance curve at same core geometry Ø=30mm, 22 turnstypical impedance curve at same core geometry Ø=30mm, 22 turns

0

10

20

30

40

50

60

0,01 0,1 1,0 10,0 100,0frequency f (MHz)

atte

nuat

ion

leve

l [dB

]

NANOPERM

Ferrite improved attenuation

below 500 kHz

improved attenuation

below 500 kHz





typical impedance curve for different core geometriestypical impedance curve for different core geometries

20

10 100 f [kHz]

impe

danc

e Z

[k Ω

]

4

12

1.000 10.000 100.000

NANOPERM∅ = 40 mm

Ferrite∅ = 63 mm

volume reduction

> 50%

volume reduction

> 50%




0

20

40

60

80

100

120

0,1 1 10 100frequency f [MHz]

nois

e le

vel [

dbµV

]

Ferrite Ø: 63mm, 3x22 turns, m = 380g

NANOPERM Ø: 40 mm, 3x32 turns, m = 94g

achieving more stringent noise limits even at a smaller build volume





Comparison of build volume Nano/Ferrite Chokes

NANOPERM-chokeIN = 3 x 25A @ 60°C

LN = 3 x 1,6 mH @ 10kHzm = 120g

Ferrite-chokeIN = 3 x 25A @ 40°C

LN = 3 x 1,3 mH @ 10kHzm = 350g

73 mm

39 mm25 mm

59 mm

volume reduction 60% weight reduction 65 %

volume reduction 60% weight reduction 65 %




principle of production process of rapidly quenched ribbons

melt, T= 1200°C

ribbon thickness ~20µm

v = 100km/h

Cu-wheel, T = 20°C

amorphousribbon

ceramik-nozzle

© AMT




cutting of ribbons with high precision knives




automatic winding process of tape wound cores




furnace and batch of cores for magnetic-field treatment

60 cm

300 cm




protective epoxy coating of tape wound cores




available nano products – core and choke types

160 mm

tape wound cores from

10 ... 200 mm ∅

single phase EMC chokes up to I = 60A

three phase EMC chokes

up to I = 200A

Advanced softmagnetic materials for electromagnetic compatibility … · 2011-08-17 · advanced...

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