EMCoS Studio Application Note: #29

Introduction

EMC

Stud

io/E

MCo

S A

nten

na V

Lab

EMC

oS L

td.

27 P

ekin

Str.

, Tbi

lisi,

0160

, Geo

rgia

Phon

e: +

995-

32-2

3890

91E-

mai

l: in

fo@

emco

s.co

mw

ww

.em

cos.

com

Made in Georgia

EMC

Stud

io/E

MCo

S A

nten

na V

Lab

EMC

oS L

td.

27 P

ekin

Str.

, Tbi

lisi,

0160

, Geo

rgia

Phon

e: +

995-

32-2

3890

91E-

mai

l: in

fo@

emco

s.co

mw

ww

.em

cos.

com

Made in Georgia

EMCo

S St

udio

EMC

oS L

td.

27 P

ekin

Str.

, Tbi

lisi,

0160

, Geo

rgia

Phon

e: +

995-

32-2

3890

91E-

mai

l: in

fo@

emco

s.co

mw

ww

.em

cos.

com

Made in Georgia

Filter Components Modeling

This application note demonstrates influence of 3D layout on LC filter performance. Two models of LC filter with vertical and flat alignment of CM choke are considered. Full wave Method of Moments (MoM) is applied. Simulations are performed in the frequency range from 10 kHz up to 100 MHz and are in a good agreement with measurements.

Toroidal CM Choke

Filter Components

Film Capacitor

MODELING OF 3D LAYOUT INFLUENCE ON LC FILTER PERFORMANCE

Toroidal CM Choke Parameters:

Diameter 36 mm

Inner diameter 23 mm

Height 15 mm

Chamfer 1.5 mm

Start angle, end angle 80, -75 degree

Number of turns for one coil 20

Wire radius 0.625 mm

Distance from core 0.125 mm

Orientation Right

Length 0.94 m

Nominal value 2 x 2.3 mH

Film Capacitor Parameters:

Length 27 mm

Width 11 mm

Height 19 mm

Blending 6 mm

Leg height 15.86 mm

Leg offset 1 mm

Nominal value 2.2 uF

Simulation Models and Measurement SamplesTwo variants of the filter with different placement of components are shown below, as well as their 3D models:

Toroidal CM Choke

Simulation Model and Measurement Sample of LC Filter with Vertical Alignment of CM Choke

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Simulation Model and Measurement Sample of LC Filter with Flat Alignment of CM Choke

Dielectric and magnetic parameters of EPCOS N30 (MnZn based) material were used for modeling of toroidal choke ferrite core.

Toroidal core is modelled in MoM using surface integral approach and is represented by bulk dielectric object described by its outer surface (discretized mesh contains about 2788 triangular elements). Winding is represented by 1528 wire segments. This approach gives possibility to consider directly influence of frequency dependent complex material parameters of ferrite material on impedance of coil, as well as the influence of capacitance between windings and capacitance of windings to core.

Filter components considered in three-dimensional model are two voluminous film capacitors and toroidal CM choke. All components are arranged on a printed circuit board.

EMCoS Studio Application Note: #29

MODELING OF 3D LAYOUT INFLUENCE ON LC FILTER PERFORMANCE

Comparison of Measured and Simulated Characteristic of FilterComparison of measured transmission coefficients with simulated results for both filter models is shown below. Simulation results are in good agreement with measurements.

The plot on the left shows comparison of transmission coefficients for two filter models with vertical and flat alignment of the CM choke.

From the obtained results it can be seen that at frequencies above 400 kHz performance of the filter is affected by placement of components. Difference in transmission coefficient for filters with flat and vertical CM chokes reaches 32 dB at 600 kHz and is about 20 dB at 10 MHz.

Simulated and Measured Transmission Coefficient

100MHz10kHz 100kHz 1MHz 10MHz -100

-80

-60

-40

-20

0

Frequency

S21

para

met

er[d

B]

MeasuredSimulated

Filter with Vertical CM Choke Filter with Flat CM Choke

10kHz 100kHz 1MHz 10MHz 100MHz-120

-100

-80

-60

-40

-20

0

Frequency

S21

para

met

er[d

B]

MeasuredSimulated

Simulated Transmission Coefficient

10kHz 100kHz 1MHz 10MHz 100MHz-120

-100

-80

-60

-40

-20

0

Frequency

S21

para

met

er[d

B]

Filter with vertical CM chokeFilter with flat CM choke

32 dB

20 dB

Measurements of transmission coefficients for both filter samples were performed using EMI test receiver HP8546A

Simulations were performed with MoM based TriD solver in frequency range from 10 kHz up to 100 MHz

10 kHz 100kHz 1MHz 10MHz 100MHz10-1

100

101

102

103

104

Frequency

Per

mea

bilit

y

Dielectric and Magnetic Parameters of EPCOS N30 (MnZn Based) Material

µ′µ′′

10 kHz 100kHz 1MHz 10MHz 100MHz103

104

105

106

FrequencyP

erm

itivi

ty ε′

ε′′

Frequency dependence of electric and magnetic properties of EPCOS N30 MnZn-based ferrite material is shown below:

EMCoS Studio Application Note: #29

Analysis of Radiated EM FieldsObservation of radiated EM field distribution around filter components can deliver important information about coupling between components and helps in optimization of filter layout or its placement relative to other electronic devices around.

MODELING OF 3D LAYOUT INFLUENCE ON LC FILTER PERFORMANCE

in out

B Total Near Field Distribution in XY and XZ Observation Planes(frequency 100 kHz; min level = -150 dBT; max level = -135 dBT)

Filter with Vertical CM Choke Filter with Flat CM Choke

in out

in out

in out

Near Field Observation Planes (XY and XZ)

Observation of near fields is performed on two near field areas located in XY and XZ planes.

B total near field distribution plots for several selected frequencies (100 kHz, 1 MHz, and 45 MHz) are presented below. Both filter models with vertical and flat positioning of CM choke are considered.

EMCoS Studio Application Note: #29

Conclusions EMCoS Studio provides advanced construction tools and

comprehensive simulation methodology for accurate modeling of EMC/EMI filters and investigation of the influence of 3D layout on overall filter performance, including analysis of radiated EM fields around filter components

References A. Gheonjian, B. Khvitia, D. Yeremian, Z. Kutchadze, R. Jobava,

X. Bunlon “FULL WAVE MOM SIMULATIONS OF EM INTERACTIONS IN EMC FILTERS FROM 10 KHZ TO 50 MHZ”, 17th International Symposium on ElectroMagnetic Compatibility (CEM 2014), 1-3 July, 2014

MODELING OF 3D LAYOUT INFLUENCE ON LC FILTER PERFORMANCE

in out

B Total Near Field Distribution in XY and XZ Observation Planes(frequency 1 MHz; min level = -150 dBT; max level = -135 dBT)

Filter with Vertical CM Choke Filter with Flat CM Choke

in out

in out

in out

in out

B Total Near Field Distribution in XY and XZ Observation Planes(frequency 45 MHz; min level = -150 dBT; max level = -135 dBT)

Filter with Vertical CM Choke Filter with Flat CM Choke

in out

in out

in out

EMCo

S St

udio

EMC

oS L

td.

27 P

ekin

Str.

, Tbi

lisi,

0160

, Geo

rgia

Phon

e: +

995-

32-2

3890

91E-

mai

l: in

fo@

emco

s.co

mw

ww

.em

cos.

com

Made in Georgia