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

Electric Field Shielding

14. August 2015 05:17 by Christian in EMC/EMI, Shielding
Types of Electromagnetic Coupling:1) Conducted Coupling2) Electric Field Coupling The Electric

Types of Electromagnetic Coupling: Conducted, Radiation, Magnetic Field, Electric Filed

Electric Field Coupling

The EF lines start on positive charge and end on negative charge from higher voltage conductors to lower voltage conductors. Any two conductors at different potentials (voltages) have electric field lines between them. EF shields are connected to “ground” to maximize their effectiveness.

 

     The electric field lines are passing through ungrounded metallic planes. 

 

Grounding a copper enclosure does not increase or decrease its shielding property but it reduces the crosstalk within the product itself. The ungrounded shield allows coupling signals from circuits within the shielded enclosure. If the device is connected via external cable to another module the ungrounded shield can serve to capacitively couple signals from outside the enclosure. 

Functions provided by MF-WPT system

11. August 2015 10:04 by Christian in
Stand by and Wake up The supply device is woken up by a signal from the EV. Compatibility check C

Stand by and Wake up

The supply device is woken up by a signal from the EV.

Compatibility check

Compatibility of the primary and the secondary devices is checked with the information exchanged at the initialization phase: power classes, operating frequency, magnetic coupling, circuit topology, tuning.

Initial Alignment check

The MF-WPT system will determine that the primary and secondary devices are properly well positioned relative to each other.

Start Power Transfer

The MF-WPT system is capable to transfer the power from the primary device to the secondary device upon the request from the vehicle. The MF-WPT system does not perform power transfer until the command and control communication is properly established and the primary device and secondary device are properly positioned.

Time Scheduled Power Transfer

Perform Power Transfer

MF-WPT system transfers the power from the primary device to the secondary device in accordance with the power demand of the EV. The maximum transferring power of the off-board MF-WPT system must not be exceeded. The vehicle can change the requested transfer power.

Stop Power Transfer

MF-WPT system is able to stop transfer the power from the primary device to the secondary device in accordance with the demand of the EV. The vehicle can requested stop power transfer.

User initiated Stop Power Transfer

MF-WPT system allows the user to terminate of power supply. (e.g. pushing stop button).

Safety monitoring & diagnostics

continuous monitoring of power transfer conditions

continuous monitoring of command & control communication

continuous monitoring of safety conditions

Power Transfer Monitoring: The supply device provide means to verify that the actual output power does not differ from the expected output power by a certain limit; if the limit is exceeded, it shall stop power transfer.

Thermal Monitoring:WPT systems is capable to detect metallic objects and to stop the power transfer.

Live Object Protection: WPT systems provide life object protection by design or may provide means to detect live objects and to stop power transfer.

Failure Conditions:The supply device stops the transfer in case of of power short-circuit, earth leakage, excess temperature, insulation failure, overcurrent, overload conditions.

Ventilation: Verify that the ventilation system of the area is functioning and active.







Drivers Saturday morning acquaintance…

11. August 2015 09:32 by Christian in


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