ELECTROMAGNETIC COMPATIBILITY

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ELECTROMAGNETIC COMPATIBILITY Dr. Donald
Church Senior Staff Engineer International
Rectifier Automotive Systems
November 17, 2005
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Electromagnetic Compatibility Outline

• Introduction Terms Definitions
• EMC in Product Development Activities Outputs
• EMC in the Automotive Environment Challenges
• Example Electro-Hydraulic Power Steering System
• EMC and the IEEE Education
• Questions

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ELECTROMAGNETIC COMPATIBILITY(EMC)

• Electromagnetic Emissions
• Your System Cannot Interfere With Other Systems
  or Subsystems in the Vehicle
• (e.g., FM Radio).
• Electromagnetic Susceptibility
• Your System Must Continue to Operate Correctly
• in the Presence of Interference From Others or
• Transient Disturbances.

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ELECTROMAGNETIC INTERFERENCE (EMI)

• Conducted Interference
• Enters/Exits on Wires for Power or Control
• Radiated Interference
• Enters/Exits Through the Air
• Emissions Must be Controlled to Protect
• AM FM Radio Stations
• Aircraft Communications Navigation
• Emergency Services Land Communications

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EMI MEASUREMENT
Spectrum Analyzer Screen
Units dBuV
50dBuV 316uV
15uV
Frequency 100kHz 100MHz
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EMC in Product Development

• Typical Development Cycle Outputs
• Product Specification
• System Architecture
• Physical Design
• Product Qualification

• Corresponding EMC Outputs
• EMC Requirements Analysis
• EMC Concept Review
• EMC Design Review
• EMC Lessons Learned

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EMC in Product Development
Typical EMC Activities During Product Development
Specification Architectural/System Design
Detailed Design Prototype/Qualification

Define the EMC requirements (5 types). Which
directives apply? Ensure the standards are
understood. What are the implications? Propose
preliminary EMC design concepts. Create the EMC
test plan. Propose PCB design strategies. Review
Power Stage Concept for EMC. Do an EMC risk
analysis. Implement the strategies and
concepts. Do pre-screening tests and
simulation. Do formal certification
testing. Re-design Re-test? Failures here are
expensive!
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EMC In The Automotive Environment

• Harsh Environment
• Power Line Transients
• RF Interference
• Electrostatic Discharge
• Power Line Electric Magnetic Fields
• High Reliability
• 1 ppm Goal
• Fail Safe is Critical
• Extreme Cost Sensitivity

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EMC In The Automotive EnvironmentSusceptibility
Power Transients Inductive Load
Switching Voltage Sag Load Dump RF
Immunity On-Board Transmitters Radio
Stations Airport Radar Systems Sensors are Most
Vulnerable Electrostatic Discharge (ESD) Up to
15kV
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EMC In The Automotive EnvironmentEmissions
Radiated Emissions Very Sensitive
Receivers Distance to the Antenna 50dB Lower
Than Commercial Limits Cables Are Unintended
Antennas PCB Traces Also Radiate Digital
Circuits Are The Main Source
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EMI Lesson 1 Remember Fourier!
The Energy in a Trapezoidal Waveform is a
Function of the Pulse Width and the Rise and Fall
Times.
Example 20kHz waveform with 10ns rise fall
times. F1 13kHz F2 32MHz
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ELECTRO-HYDRAULICPOWER STEERING SYSTEM
Hydraulic Pump

• Electronic Control Unit
• Three-Phase Inverter
• Microcontroller S/W
• Sensors
• CAN Bus

Three-Phase Brushless DC Motor
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Conducted Emissions Results
Test Conditions Typical Load, PWM _at_ 20-30A,
1,000RPM
PWM Harmonics
Load Z
Fast Edges I/O
Power Stage I/O
Low Frequency 150kHz - 30MHz
High Frequency 30MHz 100MHz
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EMC AND THE IEEE

• Ancora Imparo I Am Still Learning
• Michelangelo at Age 87
• IEEE EMC Society
• IEEE Annual EMC Symposium
• NARTE The IEEE EMC Society
• Fostering and promoting Technical Awareness,
• Education and Achievement in EMC

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EMC Summary

• What it is and why it is important
• Designing Early for EMC
• EMC Challenges in the Automotive Environment
• Example of a Certified Automotive Component
• Continuing Education Through NARTE IEEE

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