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

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Presentation on theme: "ELECTROMAGNETIC COMPATIBILITY Dr. Donald Church Senior Staff Engineer International Rectifier Automotive Systems November 17, 2005."— Presentation transcript:

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

2 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

3 ELECTROMAGNETIC COMPATIBILITY (EMC) 1.Electromagnetic Emissions Your System Cannot Interfere With Other Systems or Subsystems in the Vehicle (e.g., FM Radio). 2.Electromagnetic Susceptibility Your System Must Continue to Operate Correctly in the Presence of Interference From Others or Transient Disturbances.

4 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

5 EMI MEASUREMENT Units: dBuV 50dBuV = 316uV Frequency 100kHz – 100MHz Spectrum Analyzer Screen ~15uV

6 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

7 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!

8 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

9 EMC In The Automotive Environment: Susceptibility 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

10 EMC In The Automotive Environment: Emissions 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

11 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 ~ 13kHzF2 ~ 32MHz

12 ELECTRO-HYDRAULIC POWER STEERING SYSTEM Hydraulic Pump Electronic Control Unit Three-Phase Inverter Microcontroller & S/W Sensors CAN Bus Three-Phase Brushless DC Motor

13 Conducted Emissions Results Test Conditions; Typical Load, 20-30A, 1,000RPM PWM Harmonics Power Stage & I/O Load ZFast Edges & I/O Low Frequency; 150kHz - 30MHzHigh Frequency; 30MHz – 100MHz

14 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

15 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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