CE Analyst Overview | Conducted Emissions Analysis Overview

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Conducted emissions analysis overview
EMI ANALYST Software Suite

• Intuitive ? Accurate ? Effective

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EMI Analyst is a 4-in-1 EMI Analysis Tool

• EMI Analyst calculates electromagnetic
  interference for cable-connected circuits
• Conducted Emissions CE Analyst
• Audio and radio frequency noise emitted on cables
• Conducted Susceptibility CS Analyst
• Interference induced by noise on cabling
• Radiated Emissions RE Analyst
• Electric and magnetic fields emitted by cables
• Radiated Susceptibility RS Analyst
• Noise induced by electromagnetic fields on cables

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What does CE Analyst do?

• Calculates RF current and voltage induced on
  cables and circuitry by active circuits

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EMI Analyst Covers All Frequency Domain
Conducted Emissions (CE) Specifications

• All industries
• Consumer and Industrial
• Aviation
• Automotive
• Military and Space
• All frequency ranges
• Audio Frequency, 10 Hz 150 kHz and up
• Radio Frequency, 10 kHz 152 MHz and up

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Typical Audio Frequency CE Setup

• Military and Space
• CE101, MIL-STD-461G/F/E/D
• CE01, MIL-STD-461C
• Automotive
• CISPR 25
• Aviation
• DO-160G/F/E/D/C, Section 21
• Consumer and Industrial
• IEC EN 55011 and EN 55022

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Typical Radio Frequency CE Setup

• Military and Space
• CE102, MIL-STD-461G/F/E/D
• CE03, MIL-STD-461C/B/A
• Automotive
• CISPR 25
• Aviation
• DO-160G/F/E/D/C, Section 21
• Consumer and Industrial
• IEC EN 55011, EN 55022

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What Information is Needed?

• Before you start the analysis, collect
• Frequency range of the analysis
• CE test limit
• Active circuit waveforms
• EMI filter schematic
• Cabling configuration
• End circuit schematic

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Conducted Emissions Example

• Switch Mode Power Supply (SMPS)
• For this example, MIL-STD-461F method CE102

Frequency Range 10 kHz 10 MHz CE102 Limit 94
60 dB?V EMI Filter Low pass, T-section Cabling
configuration Shielded wire pair over ground
plane, conductive fabric tape shield End
Circuit LISN Power Supply Pass/Fail
Criteria Conducted emissions must be less than
CE limit
Block Diagram
Circuit Schematic
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Frequency Range

• Start Stop frequencies
• Log or Linear scale
• Resolution
• Pts / Decade for Log Scale
• Hz for Linear Scale
• Example MIL-STD-461F, CE102
• Range 10 kHz 10 MHz
• Scale Log
• Resolution 90 pts / decade
• 10 kHz 150 kHz in 1 kHz steps
• 150 kHz 10 MHz in 10 kHz steps

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CE102 SMPS Noise Source

• Switching power supply produces
• Differential mode current
• Common mode voltage
• EMI Analyst? needs only circuit waveforms from
• Datasheets
• Circuit analysis output
• Oscilloscope measurements

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SMPS Interference Noise Source
Input DM Current
Input CM Current
FET SwitchingVoltage
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Cabling Configuration

• 8 built-in templates
• 4 shielded, 4 unshielded
• Enter
• Physical dimensions
• Conductor and dielectric materials
• Computes
• Characteristic impedance
• R, L, C values

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Cabling Configuration

• Shielded Wire Pair Over Ground Plane for this
  example
• 18 AWG wires
• Twisted, shielded pair
• 5 cm above aluminum ground plane per MIL-STD-461F
• Fabric tape shield. Properties are defined on
  Transfer Impedance form

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Conductive Fabric Tape Shield

• Laird 86203 Nickel/Copper Black Fabric Tape

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Conductive Fabric Tape Properties

• Conductive Layer
• Nickel over Copper-plated polyester fabric
• Adhesive Layer
• Acrylic, conductive

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Fabric Resistivity and Adhesive Resistivity

• Thickness of metalized fabric is not specified
• Fabric Adhesive 0.13 mm
• Assume fabric is 0.065 mm (half)
• Surface Resistivity
• ?? ?? ?? ?? O ????????????
• ?? ???????????? ???? ?? 0.065 ???? ?? 0.06 O
  ???????????? 3.9 ?? 10 -6 O-??
• ?? ???? 1.68 ?? 10 -8 O-??
• ?? ?? ???????????? ?? ???????????? ?? ????
  232.14
• Adhesive Resistivity
• ?? ????h?????????? 25.8 ?O ????.-?? , assuming
  metallized fabric is much more conductive than
  adhesive

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End Circuits

• Schematic capture
• Ladder network
• Passive components (R, L, C, and magnetically
  coupled)
• Left-End of cable
• EMI filter for PS circuit
• Right-End of cable
• LISN circuit

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Left-End Circuit EMI Filter
Input Power Filter Schematic
EMI Analyst Filter Schematic
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Right-End Circuit LISN and DC Power Supply
LISN schematic EMI Analyst LISN schematic and
power supply impedance
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Analysis Results
View current and voltage at all points in the
circuit and anywhere along the length of the
cable.
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Analysis Results Animated

• Cable Input Impedance, 10 kHz to 10 MHz
• Wire1-to-Shield (blue)
• Shield-to-Ground (orange)
• Wire1-to-Wire2 (green)
• Animate any cable current, voltage, or impedance
  over frequency or cable length

Click graph to play
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Analysis Results 3D

• View cable current, voltage, or impedance versus
  frequency and position on cable
• Rotate Click drag
• Zoom Ctrl drag
• Move Shift drag
• Shown Common Mode Current

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Summary

• The preceding example computes conducted
  emissions produced by a switching power supply
  and compares results to the MIL-STD-461F, CE102
  limit.
• Conducted emissions are one of four applications
  in the EMI Analyst? Suite
• CE Analyst
• RE Analyst
• CS Analyst
• RS Analyst
• Recommended links
• https//www.emisoftware.com/blogs/emi-analysis-too
  l-emi-analyst-overview/
• https//www.emisoftware.com/blogs/what-else-can-em
  i-analyst-do/
• https//www.emisoftware.com/blogs/right-blend-elec
  tromagnetic-interference-analysis/
• https//www.emisoftware.com/blogs/6-qualities-to-l
  ook-for-in-emi-software/