Power Supply and Line Drivers


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The Control Unit in an EV Charging Station:

  • manages the human interface to the customer or operator,
  • the communication with the vehicle,
  • payment methods (if applicable) and
  • enables/disables the main power supply/inverter to charge the battery. 

Proper implementation of the control electronics will make all the difference, regardless of whether the maximum cable length from the charging station to the vehicle can only be 1.5m or 5m. It will also make a tremendous difference, if only one, two or several vehicles can be charged simultaneously.

Crosstalk from the power wires into the communication wires can largely be reduced by shielding and filtering, yet noise generated inside the control circuits cannot. Therefore, it’s important to minimise the latter, especially in the building blocks providing power to the control circuits.

CODICO has gathered a wealth of expertise in EV charging stations and control pilot wire communication in particular. The present whitepaper presents some of that expertise that can be used to make the design of EV charging stations easier for CODICO’s customers. It provides tested design examples for the power supply and the line drivers of the control circuit of an EV charging station, which produce little noise and radiation.

What You Will Learn From This Whitepaper-Series

PART 1: Supplying Power to the Control Circuit

In the first part of the whitepaper, the problems arising from DC/DC conversion are explained. Furthermore, selected DC/DC converters are presented that produce low emissions and operate cost-efficiently.

Finally, we describe a low-emission 3-phase AC/DC auxiliary power supply for feeding the control circuits.

PART 2: Driving the Control Pilot Wire (CP)

The second part will promote low-cost circuitry with low emissions to drive the control pilot wire. The control pilot wire is used to establish communication between the charging station and the vehicle according to SAE J1772 and IEC 61851. The control pilot wire also carries the power line communication (HomePlug Green Phy) in those charging stations that use digital communication.