Clemson Automotive Electronics Research - Clemson Vehicular

Automotive EMC Workshop

Capable and Reliable Electronic Systems

Design

Clemson Vehicular Electronics Laboratory

Device Detection and Monitoring of Unintentional Radiated Emissions

October 5, 2012

Todd Hubing Clemson University

Clemson Vehicular Electronics Laboratory - 2012

CVEL Core Capabilities

2

Design for Electromagnetic Compatibility

Design for Reliability

EM Modeling of Components and Systems

Analysis of Unintentional EM Emissions

EMC Requirements and Key Design Considerations

Radiated Emissions Radiated Susceptibility

Transient Immunity

Electrostatic Discharge

Bulk Current Injection

• 1 HF GND • Risetime Control • Filtered I/O • Adequate

Decoupling • Balance Control

• 1 HF GND • Filtered I/O • Adequate


• LF Current Path Control

• Chassis GND on board

• Filtered I/O • Adequate

Decoupling

• LF Current Path Control

• Chassis GND on board

• Filtered I/O • Adequate

Decoupling

• 1 HF GND • Chassis GND on

board • Filtered I/O • Adequate


3

CVEL is the only U.S. laboratory to guarantee that the components they design will meet all automotive EMC requirements.


Maximum Coupling Calculations

4

PORT 1 PORT 2

Calculate Maximum Possible S21 Maximum Radiated Emissions Calculator (MREMC)


FCC Emissions Test

All electronic devices generate electromagnetic

emissions

Detection of Electronic Devices

5


Typical Field Strengths

FCC Class A Device at 30 m ~30 µV/m

FCC Class B Device at 30 m ~10 µV/m

These field strengths are readily detectable and can be much stronger than fields from

intentional transmitters located further away.


6


Detecting unintentional emissions from electronic devices is simply a matter of recognizing the desired signal when it is buried in the “noise” from hundreds of other sources (both intentional and unintentional).

There is ample signal strength to detect these devices!


7



8

► AM/FM Demodulation ► Observation of Side Bands ► Short Term FFT ► Frequency Domain Signature ► Time Domain Signature ► Wavelet Filtering ► Singularity Expansion Method ► Combinations of the above

Techniques developed to identify and trace sources of EMI


Can we identify electronic devices based on their unintentional electromagnetic emissions?

0 0.5 1 1.5 2 2.5x 108

-40

-20

0

20

40

60

80

Freq [Hz]

Am

p [d

BuV

]

Buried signal


9


Can Devices Be Uniquely Identified?

10

Radiated emissions were recorded from a variety of radio receivers used in IEDs.

Results were analyzed by:

Emission characteristics were used to build an instrument capable of automatically detecting and identifying emissions.

Extracting characteristics of emissions in both the time and frequency domain.

Re-sampling high-frequency electromagnetic recordings at audio frequencies to demonstrate unique characteristics of signals.


-80

-60

-40

-20

0

Time (sec)

Freq

uenc

y (H

z)

0 5 10 15

x 10-5

0

1

2

3

4

5x 10

8

0 0.2 0.4 0.6 0.8 1 1.2 1.4 1.6 1.8 2

x 10-4

-0.1

-0.05

0

0.05

0.1

Time (sec)

Tim

e do

mai

n am

plitu

de)

Remote Control Toy Truck

Receiver

Transmitter

-60

-40

-20

0

Time (sec)

Freq

uenc

y (H

z)

0 5 10 15

x 10-5

0

1

2

3

4

5x 10

8

0 0.2 0.4 0.6 0.8 1 1.2 1.4 1.6 1.8 2

x 10-4

-0.06

-0.04

-0.02

0

0.02

0.04

Time (sec)Ti

me

dom

ain

ampl

itude

)

http://www.cvel.clemson.edu/Projects/cvel_proj_edd.html



-80

-60

-40

-20

0

Time (sec)

Freq

uenc

y (H

z)

0 5 10 15

x 10-5

0

2

4

6

8

10x 10

8

0 0.2 0.4 0.6 0.8 1 1.2 1.4 1.6 1.8 2

x 10-4

-0.1

-0.05

0

0.05

0.1

Time (sec)

Tim

e do

mai

n am

plitu

de)

Wireless Doorbell 1

-60

-40

-20

0

20

Time (sec)

Freq

uenc

y (H

z)

0 5 10 15

x 10-5

0

2

4

6

8

10x 10

8

0 0.2 0.4 0.6 0.8 1 1.2 1.4 1.6 1.8 2

x 10-4

-0.2

-0.1

0

0.1

0.2

Time (sec)Ti

me

dom

ain

ampl

itude

)

Receiver

Transmitter



-60

-40

-20

0

Time (sec)

Freq

uenc

y (H

z)

0 5 10 15

x 10-5

0

2

4

6

8

10x 10

8

0 0.2 0.4 0.6 0.8 1 1.2 1.4 1.6 1.8 2

x 10-4

-0.06

-0.04

-0.02

0

0.02

0.04

Time (sec)

Tim

e do

mai

n am

plitu

de)

Wireless Doorbell 2

-60

-40

-20

0

20

Time (sec)

Freq

uenc

y (H

z)

0 5 10 15

x 10-5

0

2

4

6

8

10x 10

8

0 0.2 0.4 0.6 0.8 1 1.2 1.4 1.6 1.8 2

x 10-4

-0.2

-0.1

0

0.1

0.2

Time (sec)Ti

me

dom

ain

ampl

itude

)

Receiver

Transmitter



-80

-60

-40

-20

0

Time (sec)

Freq

uenc

y (H

z)

0 5 10 15

x 10-5

0

1

2

3

4

5x 10

8

0 0.2 0.4 0.6 0.8 1 1.2 1.4 1.6 1.8 2

x 10-4

-0.1

-0.05

0

0.05

0.1

Time (sec)

Tim

e do

mai

n am

plitu

de)

Wireless Phone

Receiver



Time (sec)

Freq

uenc

y (G

Hz)

0 2 4 6 8 10 12 14 16 18

x 10-5

1

0.5

0

0 0.5 1 1.5 2

x 10-4

-0.4

-0.2

0

0.2

0.4

0.6

Time (sec)

Vol

tage

(vo

lt)

Digital Camera http://www.cvel.clemson.edu/Projects/cvel_proj_edd.html


Video Camera

-60

-40

-20

0

Time (sec)

Freq

uenc

y (H

z)

0 5 10 15x 10-5

0

5

10 x 108

0 0.5 1 1.5 2x 10-4

-0.2

-0.1

0

0.1

0.2

Time (sec)

Tim

e do

mai

n am

plitu

de)



Filtering of Noise

Toy Truck

Reference

In noisy environment

Processed representation of reference

Filtered representation of signal in noisy environment


Automatic Detection/Identification

18

► Automatic detection and identification has been demonstrated with 100% accuracy in noisy environments

► Currently detecting receivers 10 m away using readily available equipment with no analog filters or amplifiers

Significantly improved algorithms and more sophisticated instrumentation promises a substantial increase in standoff distance


Our latest detection algorithms are able to recognize the presence of signals that are deeply buried in the noise from other sources, even when those sources are operating at the same frequency.

Automatic Detection/Identification


Electronic System Failure Prediction/Detection

20

Monitor emissions to look for specific failure indicators.

Monitor emissions to look for any departure from normal.

Two approaches to failure prediction/detection

Analogous to listening for engine knock or wheel bearing whine in an automobile

Analogous to hearing a strange noise coming from the engine


Power Inverter Research

21

Active Cancelation of Common-Mode

Currents

Passive Filtering of Common-Mode

Currents

< 30 MHz

> 30 MHz

Reducing Emissions from 3-Phase Motor Drivers


Identifying MOSFET and IGBT Failures Before They Occur

22

PWM Switching Waveform (Low-side Drain Voltage) of a Power Inverter MOSFET


Identifying MOSFET and IGBT Failures Before They Occur

23

Pole Locations Corresponding to Low-Side Oscillation

Application of Matrix Pencil Method with Pre-Conditioning


CVEL Core Capabilities

24

Design for Electromagnetic Compatibility

Design for Reliability

EM Modeling of Components and Systems

Analysis of Unintentional EM Emissions

Clemson Automotive Electronics Research - Clemson Vehicular

Documents

Transcript of Clemson Automotive Electronics Research - Clemson Vehicular