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

EV require higher power for the electric drive components and higher voltage (900 V) in the high voltage bus. The HV Bus is built as a completely insulated power supply network with cables most often shielded.

The main components of the automotive electric drive are:

• electric motor (the connection between converter and motor must be very short)
• power converter (the main source of EMI due to high speed switching devices with changing pulse patterns)
• power supply (traction battery providing power to the converter is a main part of the path for EMI)
• lines connecting the above components

Each of these components acts as a path for electromagnetic emissions:

• RF noise emissions due to the ratio between the size of the power converter and the frequency of the EMI.
• The high-voltage system is insulated and does not use the car body as return conductor like the low-voltage supply system. However, the high-voltage and the low voltage cables are arranged closely to each other, one important coupling path being the crosstalk between the different lines.
• The drive system can be either noise source or part of the coupling path within EV electrical system.

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

Fast charging shortcomings:

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