201606_ferrites,_cmc,_and_power_transformer_(2)e

1

Soft Ferrite SpecificationCMC、 Power Choke

and Transformer(A)Soft Ferrite(B)CMC(C)Power

Choke/TransformerBy Ray LaiJune 2016

Table of ContentB.CMC

B1. CMC PrincipleB2. CMC DesignB3. CMC Failure Example

C.Power Choke and TransformerC1. Power ChokeC2. Coupled Inductor (Flyback Transformer)C3. SMPS Transformer

2

B. Common mode choke CMC)3

Magnetic components play key role in power conversion system

4

B. Common mode choke (CMC)

Magnetic components which ferrites can make

5 Input side CMC generally adopts closed-loop core (toroid) or ET core. On the high frequency output side, HI configuration is also popular (usually mirror lapping required, easy for auto winding)

Hi-Lo side isolation is required by the spacers of bobbin


6


SMD Pulse Transformer SMD Common Mode Choke

Conventional Newer

磁環

7

B1. CMC Principle CMC is used to filter out the “common mode” noise with the minimal effect on the main electrical quantity (no matter signal or power) (EN55022 requires EMI conduction reduction in 150kHz~500kHz)

Two independent choke(Two cores)

CMC(One core)

8

B1. CMC Principle

Ampere’s right-hand rule

The main (load) current flows opposite direction in the two windings, so its flux canceled each (differential mode), only leakage can cause the core to saturate.

CM noise generates flux in the same direction, so it sees high impedance

: noise frequency ，L: CM inductance

9

Measurement of common mode

Measurement of differential mode (leakage)

Why “Peak” frequency different?

Parasitic C of windings

B1. CMC Principle

1

L 1 2 0

1 2

0

3

K

COUPLING=

K 2

1TX2 2 _ 1 4 _ 1 3 _ 3 E 2 7

L 1 = L 2

K

COUPLING=

K 1

1TX2 2 _ 1 4 _ 1 3 _ 3 E 2 7

L 1 = L 1R 17 5 0

2

V 1

TD = 0

TF = 1 uP W = 4 9 uP E R = 1 0 0 u

V 1 = -1

TR = 1 u

V 2 = 1

L 2 2 01 2

R 2

0 . 1

R 3

0 . 1

10

Q: WHY?

A: Inductor is a LP filter itself

B1. CMC Principle

11

1

L 1 2 0

1 2

0

K

COUPLING=

K 1

1TX2 2 _ 1 4 _ 1 3 _ 3 E 2 7

L 1 = L 1

L 2 = L 2R 17 5 0

2

V 1

TD = 0

TF = 1 uP W = 4 9 uP E R = 1 0 0 u

V 1 = -1

TR = 1 u

V 2 = 1

L 2 2 01 2

R 2

0 . 1

R 3

0 . 1

B1. CMC Principle

12

B2. CMC Design The impedance of CMC (resistance and reluctance) are from the complex permeability of the material (u‘ and u“), and the frequency of u’ is the key to CMC design

13 Ignoring the wiring resistance, (leakage) inductance, and parasitic capacitance, the impedance of CMC is

Using Q as the quality index of CMC or power choke must consider its load situation ( and frequency, voltage)

Q in power and signal level are not equivalent to each other！

Core loss factor

B2. CMC Design

14

Critical in common mode choke design selection

𝜇𝑖× 𝑓𝑟𝑒𝑞𝑢𝑛𝑒𝑐𝑦 ≈𝑐𝑜𝑛𝑠𝑡𝑎𝑛𝑡

B2. CMC Design

15

where:fg – gyromagnetic critical frequencyγ ~0.22 ΜΗz m/A is the gyromagnetic ratio for an electron

i.e. the ratio of magnetic moment and torqueBs – saturation flux densityμi,0– initial permeability * J. L. Snoek, Physica 14, 207, 1948

sig Bf 34)1( 0, Snoek Limit

A2. Specifications – Power/High Perm Materials

For higher perm material to have wider frequency response is against the law of physics.

16 Characteristics of Mn-Zn and Ni-Zn Ferrite in the sense of ui vs. frequency All governed by Snoek limit.

A2. Specifications – Power/High Perm Materials

Limit is here roughly by the advances of ferrite research

17 CMC is in transformer configuration (coupled inductor) yet is not used in transformer way

Usually by adding a pair of small capacitor (Y capacitors) on the AC input side to form an L-C low pass filter can suppress the noise better

the L2-C configuration will have -3dB corner frequency

low pass corner frequency.

The parasitic capacitor affects the performance (by changing |Zcmc| in a more complex way

B2. CMC Design

18 Case 1: A10EP7L failed in 150k~200kHz EMI conduction

Z_peak @ 300kHz?!

Turns’ number: 80

B2. CMC Design


By material u’ and u”, the frequency of Z_peak > 1MHz

B2. CMC Design

20

The parasitic capacitance cannot be ignored in this case

𝑍 𝑐𝑜𝑟𝑒=(𝑁2 𝜔𝜇0

𝐴𝑒

𝑙𝑒)¿

𝑍 𝑐𝑎𝑝=1/ 𝑗𝜔𝐶𝑝

|𝑍𝑐𝑜𝑟𝑒|=|( 1𝑍𝑐𝑜𝑟𝑒

+ 1𝑍𝑐𝑎𝑝 )

− 1|

Case 1: A10EP7L failed in 150k~200kHz EMI conduction

B2. CMC Design


Just by 4pF, the amplitude and peak of the impedance of CMC totally changed

B2. CMC Design


In the end, it is A05-90T that works!

B2. CMC Design


In the end, it is A05 that works!

Measurement matched the calculation from the material table

B2. CMC Design

24 Case 2 ： Geometric Fantasy of CMC

Due to the size and material limitation, someone was thinking if bigger Ae (or higher Ae/le) available by the following topology change.

To replace the simple toroid

B2. CMC Design

25

As long as the windings are still on two sides of the core, any of the above ways cannot increase Ae or yield more flux passing surface. Only increase the leakage of the CMC which is unwanted.

B2. CMC Design Case 2 ： Geometric Fantasy of CMC

The same for this one


27

If winding are on the center part, than the right (EE) and left cores are equivalent.

Q: Why did not see CMC doing this way?A: next page


28

28

High-low side insulation is the basic safety regulation requirement.


29

High Permeability Material List for CMC [ACME]

Symbol UnitMeasuring Conditions High Permeability Materials

Freq. Flux den. Temp. A05 A07 A071 A10 A102 A121 A151

Initial Permeability μi 　 ≤ 10KHz 0.25mT 25°C 5000± 25%

7000± 25%

7000 ± 25%

10000± 30%

10000± 30%

12000± 30%

15000± 30%

Realative Loss factortan δ/μi 10-6

10KHz< 0.25mT 25°C ＜ 4 < 8 < 8 ＜ 10 ＜ 10 ＜ 10 ＜ 10

100KHz ＜ 15 < 30 < 30 ＜ 60 ＜ 60 ＜ 60 <110Saturation Flux Density

Bms mT 10KHz H=1200A/m

25°C 440 400 440 410 380 380 400100°C 300 200 280 210 180 180 170

RemanenceBrms mT 10KHz H=1200A/

m25°C 80 150 80 140 95 130 220

100°C 90 110 60 110 75 110 100

Temperature Factor of Permeability αF 10-6/°C 10KHz < 0.25mT

0~20°C 0~2 -1 ~ 1 -1~1 0~1.5 -1 ～ 1 0~1.5 -1~120~70°C 0~2 -1 ~ 1 -1~1 -0.5 ～ 1 -1 ～ 1 -0.5~1 -1~1

Hysteresis Material Constant ηB 10-6/mT 10KHz 1.5-3.0mT 25°C ＜ 0.8 ＜ 1.2 < 1.2 < 0.5 ＜ 1 ＜ 0.5 ＜ 0.5

Disaccommodation Factor DF 10-6 10KHz < 0.25mT 25°C ＜ 3 ＜ 2 < 2 ＜ 2 ＜ 2 ＜ 2 ＜ 2

Curie Temperature Tc °C 　　　 140 130 ≥ 145 130 120 110 110Resistivity ρ Ωm 　　　 0.2 0.35 0.35 0.15 0.15 0.12 0.1

Density d g/cm3 　　　 4.85 4.9 4.9 4.9 4.9 4.9 5

AutomotiveRecommended

B2. CMC Design

30

u

ZThis point is by LC parallel resonance, where L is pure winding, C is layer parasitic. Baiscally it becomes space EM issue, nothing to do with ferrite.

Solution: (1) increase layer space (2) change wire diameter (3) change turns number or core size

B2. CMC Design

31

Winding is a kind of art, the unique technic for winding house to survive

B2. CMC Design

Not really there

32

Winding experiment from BW ( 百徽 ) engineer (2014-06-27 data)

B2. CMC Design

33

Useless and way of winding dependent.

B2. CMC Design

34

B3. CMC Failure Example Failed replacement attempt: - A12URT19C

Trying to use the custom made A12URT19C to replace A10T20x11x10C, but the customer found when the load current > 3A, CMC failed like not there.

1. To replace, check if Ae/le is better first, as least should be equivalent.

For T20x11x10C, Ae/le=0.951 only 21 turns needed for A10 to have 5mH low frequency inductance

　 Outer D Inner D Height 　　 d1 d2 h 　mm 20 11 10 NominalNominal 　　　　C1 1.051E+00 mm^-1 uo 1.25664E-06C2 2.406E-02 mm^-3 ui 10000Le 45.911 mm AL 1.19567E-05Ae 43.683 mm^2 N 21Ve 2,005.527 mm^3 L 5.273E-03

35

The Ae/le of URT19C is 0.263 ， A12 takes 36 turns to have the 5mH

Geometrically， URT19C fails！

B3. CMC Failure Example

36

2. Check if new material yields a better frequency response


37

2. . Check if new material has better frequency response EN-55022 EMI Conduction frequency range is 150kHz~500kHz ，A12URT19C fails!


38

3. For current > 3A, CMC lost its function, the conduction noise like the case of no CMC

Only leakage will cause CMC to saturate then fail


à R12k (27Ts) A07(A121 36Ts) A10 (31Ts)

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35




4. ui and bandwidth of A12 is inferior than R12K (in this case), by the same core A12 of 36 turns equals to 27 turns of R12. Surely A12 has more leakage.

36


4. By comparing the datasheet, A12 is as good as R12K (though not fully sintered), but sometimes it is just not the case in real product.

37


43 Big part of MnZn CMC complaints, beside Z and bandwidth, are related to the coating damage caused by winding process (NiZn has no this issue)

Flux linkage from load current cancels each other, so the differential voltage across CMC =0


44

When short happens, due to high is high thus it will cause sparks or even crack the core when the coating insulation cannot sustain.


45

When windings are partially shorted, if the coating layer sustains, the imbalance on the MMF will heat up the core till it breaks down.


46


When windings are partially shorted and the coating layer broken, the instantaneous high current may cause the core to explode.

47 EN55022 specifies the EMI/EMC regulation, in HF band, NiZn is used and it’s the winding skill that matters most, beside the ferrite property.


48

C. Power Choke and Transformer Frequent asked questions:1. When measuring core loss of a gapped part, it is much higher

than calculating it using the core curves in the catalog. WHY?(explained)

2. How to derive the core height from a fixed core footprint for a given power level in power transformer? Or for a fixed core geometry, what is the most fit height for maximal power density?

This is a difficult to answer question and might be no answer. The only certain thing is that for a fixed core geometry, there is a maximal power density it can go for two-winding model (and it is SMPS topology dependent), there is no universal formula for any winding number and any switching topologies.

Switching transformer design is still a case-by-case issue to make the engineer’s career interesting.

49

2. How to derive the core height from a fixed core footprint for a given power level in power transformer? Or for a fixed core footprint, what is the most fit height for maximal power density?

Even better winding arrangement can increase the power handling capability of a transformer in the sense of temperature rise.

C. Power Choke and Transformer

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51

Ci

CoN2

N1

D1

Ci

D2

LR

S1

2

1

3

S2

2

1

3

N2

Vo

>iL

-

+

-

-

++

Vi Vin

12

RloadCD

LSW2

1

3

+ +

--

Vo

+ -

For the below half-bridge converter, its equivalent is a buck converter, with Vin=10V, Vout=5V, Pout=100W, and switching frequency= 100kHz. Determine the inductance and design the inductor.

Half-Bridge Converter is a Buck Topology

Note: In practical design, there are many factors to consider. There is some degree of freedom in choosing the core type, but not with no limitation at all.

C1. DC-DC Power Choke

52

C1. DC-DC power choke

53

Vin

12

RloadCD

LSW2

1

3

+ +

--

Vo

+ -

Assuming CCM mode,

Then the V-I relationships are

where and

is called voltage regulation and is determined by L and C.

=


54

time

S1 on S1 off

Ts 2Ts

DTs (1-D)Ts

3Ts

time

ON

OFF

0

Vin-VoV

-Vo

time

0

A

i1

i2

1

2∆ 𝐼 𝐿∝𝐿

By volt – second balance


55

, so the duty ratio D=0.5. The switching period (two switches in half-bridge configuration)

Determine the Inductance L:

If (This is a design spec that must be given)

=

Why the switching frequency gets higher and higher? if , then

= Size and windings of the inductor will substantially increase


56 How to realize the inductance? Tackle it from the “sustained power/energy” concept

“Area product” this parameter links the electro-mechanical nature of a core.

: peak current : maximal current density on the wire, safety related : NOT , the maximal allowable flux density under this opwerational condition, it directly relates to the volt-second balance. : winding space means the current sustainability : core space means the voltage sustainability


57C1. 功率電感 (DC-DC power choke)

: 鐵芯繞線空間

銅線有絕緣塗層和不可利用的線間空間代表實際上可用的面積比例典型值 :0.5 低壓電感0.25 to 0.3 離線變壓器0.05 to 0.2 高壓變壓器 ( 幾 kV)0.65 低壓銅箔型電感器

: 鐵

由來選擇鐵芯尺寸

58

Pick EE22 ( easier for obtaining ),

CORESDIMENSIONS (mm) EFFECTIVE PARAMETERS

A B C D E F C1(mm-1) Le(mm) Ae(mm2) Ve(mm3) Wt(g/set)

EEL22 22.25 ± 0.30

15.26 ± 0.30 5.70 ± 0.30 5.70 ± 0.30 15.50min 11.20 ± 0.30 1.77 65.00 37.00 2405.00 11.74

Faraday’a law of induction

Turns number know now, find the gap


59

Precise doesn’t really matter.

C

AWG Dia-mm Max OD (mm) Area (mm^2) 　 R-ohm/cm R-ohm/mm R-ohm/mm

9 2.9063 2.98 6.634E+00 2.599E-05 2.599E-05 2.599E-06 3.49086E-06

Pick AWG#9. all winding area OK!


60 Core type and winding are determined, now need to select the core material to work normally under the frequency. Bmax should be as high as possible (1st), Pv minimal (2nd), efficiency high (by the trade-off with $$)

The material can affect all the above design choices. In DC-DC choke design, the inductance is set by or , i.e., with DC content

HHrev

ACHB

µµ

0

1

)

The upper limit of also is material related.

Note ： most of Hdc will drop across the gap, but the H across the core still follows the original BH curve


61

Reversible permeability at different operating points


62

ITEM FINISHED PRODUCT

　 + -A 10.40 0.15 0.20B 5.30 max 　C 8.85 0.10 0.15D 4.40 0.10 0.10E 0.80 0.10 0.10F 2.95 0.10 0.05H 8.05 0.15 0.15K 8.35 0.15 0.15T 2.15 0.10 0.05　　　　A1 10.40 0.15 0.20C1 8.85 0.10 0.15I 2.00 0.05 0.05

Real complaint:

C1. DC-DC power choke –failure example

63

SPEC nH DC-Bias nH DC-Bias nH DC-Bias nH DC-Bias270.00 (56A) 270.00 (56A) 270.00 (56A) 270.00 (56A)

Usl 291.60 　 291.60 　 291.60 　 291.60 　Lsl 248.40 190nH

Min 248.40 190nHMin 248.40 190nH

Min 248.40 190nHMin

Test cond. 100KHz/1V 100KHz/1Vgap 0.084mm 0.088mm 0.084mm 0.088mm

Process C/H ground， T/I ground C/H ground， T/I not groundCritical C:8.80~8.85,T： 2.14~2.2 C:8.80~8.85,T： 2.41~2.44

1 283.0 153.0 271.0 212.0 271.2 198.9 269.9 210.1 2 279.0 196.0 268.0 216.0 270.9 208.3 269.1 212.0 3 283.0 155.0 265.0 210.0 275.3 197.1 267.9 211.0 4 283.0 159.0 267.0 205.0 273.5 209.3 269.3 215.0 5 281.0 174.0 260.0 214.0 274.9 198.0 272.0 206.9 6 283.0 178.0 261.0 214.0 276.0 203.0 272.7 208.0 7 285.0 165.0 266.0 204.0 274.3 216.0 271.9 215.0 8 278.0 182.0 264.0 215.0 275.3 198.6 267.4 210.0 9 283.0 156.0 274.0 200.0 276.8 200.7 270.0 206.0

10 282.0 167.0 　　 276.0 203.3 270.2 210.4 Max 285.0 196.0 274.0 216.0 276.8 216.0 272.7 215.0 Min 278.0 153.0 260.0 200.0 270.9 197.1 267.4 206.0

Mean 282.0 168.5 266.2 210.0 274.4 203.3 270.0 210.4


64 “Soft Ferrite” is not soft at all. Skipping the tedious calculation, it has proven that by only adding extra 4um gap, the Bmax on the core dropped from 407mT (H=76A/m) to 389mT(H=69A/m), this tiny 20mT means the difference between pass and fail ！ Note that 56Adc generates H=3800A/m, but most of Hdc is dropped across the gap, only 76 or 69A/m is on the core.


65

B-H curve of no gap

B-H curve of with gap

By , the H drop on the core is still the same as the material B-H,excess H is shared by the air gap.


66

Illustration of the trade off between inductance and current handling capability of ferrite due to the limit of Hmax it allows.

C1. DC-DC power choke –failure example“Soft Ferrite” is not soft at all.

67 Uneven magnetic path in the loop will not work.

A_center 39.04 A_1 side 26.83 A_plate 19.93

This kind of geometry is no good for dc-dc choke ， Ae_min section will saturate first, waste the rest core area and space.

A(mm): 15±0.4B(mm): 9.8 C(mm): 7.05±0.2D(mm): 11.7±0.3E(mm): 1.9±0.1 F(mm): 3.7±0.1

𝐴𝑠𝑖𝑑𝑒

𝐴𝑐𝑒𝑛𝑡𝑒𝑟

𝐴𝑝𝑙𝑎𝑡𝑒


68

Flyback topology and 與 waveforms ofDCM

The “transformer” (coupled inductor) stores and release energy through its magnetizing inductance Lm (by Ip & Is), and decide the converter behaviors.

Why this is “inductor” instead of transformer??One current in one winding at any instant

C2. Coupled Inductor (Flyback Transformer)

69

Popular Flyback Converter Design (3-winding)Low cost adapter

CMCDC

choke

50/60Hz AC

Vin


70 The design formulae are irrelevant to he magnetic component knowhow, thus are skipped here.

Comparing the coupled inductor and the DC-DC choke, their similarities and differences are

Similarity: 1. Bsat(Bmax) as high as possible2. Gap is needed for different reason. Coupled inductor uses gap for energy

management, DC-DC choke needs gap for consuming HdcDifference:3. The permeability of coupled inductor is amplitude permeability , DC-DC choke one

is differential permeability 4. As ， usually Pv in general DC-DC choke is not an issue (Except the way of

Vicor P61 operation), coupled inductor is operated under the first quadrant of V-I (B-H) chart , but its to maximally drive the core, so Pvis an important factor like the case in transformer.


71

time

S1 on S1 off

Ts 2Ts

DTs (1-D)Ts

3Ts

time

ON

OFF

0

Vin-VoV

-Vo

time

0

A

i1

i2 ∆ 𝐼 𝐿∝𝐿

Ip Is’

DC-DC choke

Coupled inductor

time

A ∆ 𝐼 𝐿∝𝐿


All follow V-T balance principle

72

HHrev

ACHB

µµ

0

1

max0

1HH

aHB

µµ

∆ B

DC-DC Choke with Hdc, small Coupled Inductor, without Hdc, big


73 Real Design Example ： a.. By below EP0714 core drawing, get Ae/Ve/Le (P4/P47 mat’l) and compare with EP7 b. What is the power rating(W) ?? c.. If power rating < 5W, feel free to redefine the core just keeping the core’s L/W/H dimensionsFrequency 100kHz, inductance 840uH (not given in the first place, means the engineer has no enough experience)


74

IEC60205 Magnertic Geometric Parameters

a. IEC60205 for core’s geometry factor is embedded on the right

　 EP0714 EP7 　ui 2400 2400　uo 1.2566E-06 1.2566E-06　Ae 1.49E-05 1.03E-05　le 2.79E-02 1.57E-02　　　　　AL 1.604E-06 1.979E-060 gap　　　　N 106 106　 GivenL 8.40E-04 8.40E-04　AL(g) 7.476E-08 7.476E-08　lg 2.38E-04 1.67E-04m　 0.238 0.167 mm


75

b. Power Rating By original condition, none of two designs reach 5W power

Hdc 60 60　設計選擇Idc 3.39E-01 2.35E-01　Energy 4.8314E-05 2.3234E-05 JoulePower 4.83142813 2.3233873 Watt


Inductor is an “energy storing” device. The power rating actually is just the energy stored multiplied by the frequency

76

b. Power Rating By modifying the turns’ number to 120, EP0714 can sustain 6W. This is to set Hdc=60A/m (higher). Under full load, Bmax may close to saturation with lower efficiency. But it is no problem to work under 5W (with lower Hdc_max)

c. No need to do so, solved.

　 EP0714 EP7 　N 120 120　

SuggestedL 8.40E-04 8.40E-04　AL(g) 5.83333E-08 5.83333E-08　lg 3.08E-04 2.15E-04m　 0.308 0.215 mmHdc 60 60　Idc 3.84E-01 2.66E-01　Energy 6.19193E-05 2.97764E-05 JoulePower 6.19 2.978Watt

WHY?


77

C3. SMPS transformer

Basic PrototypeIdeal Model

Flux linkage and leakageApplicable Model (1st order, winding capacitance ignored)

78

Wire intrinsic inductance and leakage

Core nature defined by B-H curve

𝐵𝑚=1/𝐿𝑚

𝐺𝑐=1/𝑅𝑐


79 From ideal model, it is seen that so the efficiency can be100%. But this is impossible as current needs passing to build up the induced voltage to create the “transformer” action

When all electrical parameters determined, like DC-DC choke, the transformer core is determined by area product Ap, to have the suitable geometry for electro-magnetic conversion.𝑺𝒎𝒂𝒙=𝑿𝟏 𝑓 𝑟𝑒𝑞𝑘𝑐𝑢 𝐽𝑚𝑎𝑥 𝐵𝑚𝑎𝑥 𝐴𝑒 A𝑤 : maximal power,

: power coefficient for different excitation and core type


80

EE core for example, the Ae is uneven along the flux path. The center post has Ae_min to yield a larger winding space.

To optimize , cores for transformer usually has sectionalized Ae


81

If even Ae is required, the EE core will look like the left figure

The Ae obtained by IEC60205 tends to overestimate the transformer’s power handling capability.

In transformer design, the Ac used must be Ae_min for power calculation

In this way, Ap=Ac x Aw cannot be maximize.


•Turns:EE5: 22 : 22EP5: 28 : 28

•I have different cores:But with some I could reach the inductance with some not and also I could not reach the current with all of them!!

82 Real example: Engineers forgot to look at the basics.

EE5 or EP5 core Inductance: 350 µH (between PIN 2 and PIN 3), 100kHz, 100mV,

8mA DCBias Saturation current: approximately 2 A DC (drop of 20%) Rated current of course at least the same Operating frequency: 1 – 125 kHz Application: Transformer for LAN application

A121 EP5 N42 EP5 A10 EE5 A07 EE5

Of Course NOT！


83 Geometric facts of EE5 and EP5

This is a telecom transformer with POE (Power Over Ethernet) requirement.To have 350uH with 11 turns on EE5 and 14 turns on EP, the permeability ui must be the value shown belowi.e., no gap allowed

　 EE5 EP5Ae 2.66E-06 3.00E-06le 1.25E-02 9.70E-03uo 1.25664E-06 1.25664E-06N 11 14L 3.50E-04 3.50E-04AL 2.89256E-06 2.89256E-06ur 10817 7443


84 Under no gap situation, when 1Adc flows through one winding, (center-tapped for split the 2A)

for EE5

for EP5 Core is saturated like air!!

P4 B-H Curve


Only when Hmax (<150A/m) ， there is or permeability ， over it the core goes to saturation and no usable inductance for SMPS

Bsat= 520mT obtained at H =1200A/m, just for brag!

For ferrites, only this short portion is good for SMPS/filtering application

85 Winding technics and way of copper’s layout is the key to the success of inductor and transformer. This is also one of the factors that why magnetic component design is still a case by case issue. Good wiring can evenly distribute H can reduce leakage and noise, also can reduce iron and copper losses.


86

C. Power Choke and Transformer Winding technics and way of copper’s layout is the key to the success of inductor and transformer. This is also one of the factors that why magnetic component design is still a case by case issue. Good wiring can evenly distribute H can reduce leakage and noise, also can reduce iron and copper losses.

Minimal copper losses can be obtained through careful layout and wire type selection

87

4. Open Discussions

Thank You~

201606_ferrites,_cmc,_and_power_transformer_(2)e

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