EMC FLEX BLOG A site dedicated to Automotive EMC Testing for Electronic Modules

WPT Magnetic Field & Electric Field Exposure

21. July 2015 22:39 by Christian in
Sources: University of Michigan-Dearborn

 Human Model at the worst radiation point during slow EV charging.



Sources: University of Michigan-Dearborn



EV Conductive Charging Time

21. July 2015 22:01 by Christian in
EV Charging Time & Power Requirement Range 5 minutes 15 minutes

EV Charging Time & Power Requirement

Range

5 minutes

15 minutes

30 minutes

8 hours

100 miles

390 kW

130kW

65kW

4 kW

400 miles

1560 kW

520 kW

260 kW

16 kW

 

Fast charging shortcomings:

  •  it may compromise battery life
  • increased cost for the charging stations
  • power grid heavy loading

WPT Dynamic in-motion charging

21. July 2015 03:37 by Christian in


EV Radiated Disturbance Test for Keyless Entry

20. July 2015 11:29 by Christian in
This test simulates the effects of the radiated magnetic fields on a keyless entry system for a vehi

This test simulates the effects of the radiated magnetic fields on a keyless entry system due to close proximity to other vehicles charging systems. The charging equipment is connected to a resistive load that represents 100 % of the load of maximum.

1. Turn on the charging equipment and allow sufficient time for stabilization.
2. Locate the loop sensor 1 m from the charging equipment face or electrical interface connector being probed. Orient the plane of the loop sensor parallel to the charging equipment faces and parallel to the axis of connectors.
3. Scan the measurement receiver over the applicable frequency range to locate the frequencies of maximum radiation, using the bandwidths and minimum measurement times according to MIL STD 461 or CISPR 16-2-3.
4. Tune the measurement receiver to one of the frequencies or band of frequencies identified in step 3 above.
5. Monitor the output of the measurement receiver while moving the loop sensor (maintaining the 1 m spacing) over the face of the EUT or around the connector. Note the point of maximum radiation for each frequency identified in step 4.
6. At the point of maximum radiation, orient the loop sensor in the vertical plane to give a maximum reading on the measurement receiver and record the reading.
7. Repeat step 4 through step 6 for at least two frequencies of maximum radiation per octave of frequencies below 200 Hz and for at least three frequencies of maximum radiation per octave above 200 Hz.
8. Repeat step 2 through step 7 for each face of the EUT and for each EUT electrical connector.

Sources: MIL STD 461 or CISPR 16-2-3

EMC Requirements Analysis

13. July 2015 09:00 by Christian in
The automotive OEM EMC requirements analysis is the first step in developing an automotive

The automotive OEM EMC requirements analysis is the first step in developing an automotive component level EMC test plan.  The technical information made available by product's CTS (Component Technical Specification) is used to:

  1. review product's family description
  2. review DUT's theory of operation, physical construction, and vehicle packaging
  3. identify DUT's functions and measurable I/O test points
  4. identify critical interface signals
  5. identify potential sources of emissions
  6. define performance criteria for each test point during and after each applicable test method listed by OEM EMC specification

1. Product Family Description

  • Include a general product family description.
  • If the EMC test plan is for more than one product a description of the differences and similarities between the different HW and SW versions must be included.
  • If the maximum complexity DUT is used to represent an entire product family include an explanatory justification/rationale. This can be a matrix showing the family and all functions provided by each member of the family where the maximum complexity DUT covers all functions listed.

2. Theory Of Operation

  • Include an internal block diagram that clearly show what the DUT does.
  • Explain what all DUT's major functions and the internal block diagram.
  • Verify the block diagram against the latest vehicle wiring schematics to confirm that shows:
    • connections to battery and the ignition switch, including signal inputs such as illumination. 
    • fuses and their ratings if connected to vehicle battery.
    • regulated supply parameters if connected externally to it.
    • all external interfaces indicating interactions with other systems, sensors, switches and actuators.
    • any special wiring such as twisted and shielded.
    • where each signal return or ground wire is connected in the vehicle.

3. Physical Construction

  • product package material
  • product package location within vehicle
  • product package customer access
  • number of PCB per package
  • number of connectors per package and their drawing indicating their pin out
  • product's picture / CAD drawing
  • include a module's pin out table and interface description
  • description of product's power return ground
  • description of product case connection to the reference ground
  • show special wiring such as twisted and shielded
  • show if the product is connected internally/externally to a magnetically sensitive or controlled device
  • show product's connection to vehicle
  • specify the type of substrate for each PCB and the number of layers used

4. Identify Critical Interface Signals

  • Is there a list of critical signals included in CTS?
  • Are the items on the list consistent with information provided in sections 1 & 2?
  • Does the I/O table contain all analogue inputs, sensors and communications lines?
  • Does the D&R OEM engineer agree with the critical interfaces?

5. Identify Potential Sources of RF Emissions

  • Is there a list of potential sources of emissions included in CTS?
  • Are they reasonable and consistent with Product complexity? 
  • Examples of sources of emissions: 
    • Clocks
    • Oscillators
    • Communication interfaces
    • Local Oscillators
    • PWM signals
    • Video signals
  • There should be no potential sources of emissions around 150-270 KHz or 0.5-2 MHz due to the high risk of interference with radio reception in LW and MW bands.

6. Performance Criteria for each test point during and after each applicable test method

  • OEM Spec Test Requirements
  • DUT Operating Modes / Functional Classifications
  • DUT Input Requirements
  • DUT Output Requirements
  • Load Box/Test Support Requirements including communication bus
  • DUT Activation, Monitoring, and Functional Verification Manual
  • DUT Test Set-up Diagram
  • Detailed Test Setup and specifics for each OEM Test Method