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ELECTROMAGNETIC COMPATIBILITY TESTING IN AN ALL‐
ELECTRIC VEHICLE
Lennart E. Long and Charles R. Edelson
with Stephen W. Sauter
3‐20‐15
EXECUTIVE SUMMARY
•Purpose ‐ provide EMC awareness •Illustrate EMC process with examples
•Good news for packaging people
• Process for testing is UMTA Recommended Procedures
• Advantages of testing a functioning vehicle vs. laboratory testing
THE THREAT
•Vehicle subsystems are increasingly becoming guide by wire. •Propulsion System emissions can affect the onboard and the wayside environment.
•Non‐linear emissions can affect the on‐board systems (cell phones, games, tablets, signage).
THE PROCESS
• Electromagnetic Compatibility issues are addressed by the EMC consultant and the client agreeing on the objectives. • A proposed Test Plan (this spells out the requirements) is drafted by a consultant and reviewed and approved by the client. • Following Test Plan approval, a Detailed Test Procedure is prepared. This describes, step by step, every detail of the proposed testing. • EMC Field testing is performed. • The resulting data is analyzed to identify threats to vehicle subsystems as well as possible threats to the wayside. • A final report is prepared documenting operational compatibility of on‐board subsystems as well as vehicle compatibility with wayside receptors and radiators.
INDUCTIVE EMC
Inductive Emissions Measurement Use UMTA METHOD RT/IE01A. On‐
road vehicle must be tested with a large loop.
COUPLING CIRCUIT (IF NEEDED)
LOOP SENSOR WITH CLAMPS
INDUCTIVE EMC
Inductive interference is measured using a road loop which measures the voltage induced in that loop by the vehicle under test.
CONDUCTIVE EMC
Conductive Emissions Measurements Use Method RT/RC01A
SPECTRUM ANALYZER
PRINTER
DIGITAL RECORDER
CONDUCTIVE EMC
A current sensor is placed on the output of the low voltage
distribution network and measure any emissions which travel to
all of the vehicle subsystems. These measurements have been
taken on vehicles operated by catenary, third rail, battery, gasoline
or liquid propane.
RADIATED EMC
Radiated Emissions Measurements Use Method RT/RE01A
VEHICLE
UNDER TEST
RADIATED EMC
This test is performed on both moving and stationary vehicles. This is
what makes this so different from Lab testing of components. A fully
assembled and functional vehicle cannot be tested at various speeds
and loads in a screen room or shielded facility.
ON THE ROAD VEHICLES
• Vulnerability of today’s cars
• Real Future Threats
• Hacker Threat – Automotive EMI
• Communications with other vehicles
• EMC with the wayside and other vehicles and within the vehicle
• Emanations caused by packaging designs?
• Emanations from other vehicles
• Emanations to the traffic control loops
SUMMARY
Welcome to the ever changing world of electromagnetic reality. We, all of us, are both the cause, result, and the victims of this environment. CONTACT INFORMATION
Lennart E. Long, Engineering Consultant
Transportation Electromagnetic Compatibility
LenLong and Associates Owner, Treasurer
US DOT Technical Consultant ‐ Rail Inspection
22 Abbott Road
Waltham, MA 02452‐7840
781‐894‐3943 office/laboratory
781‐249‐5041 cell
l.long1@comcast.net
l.long@juno.com