The Charge Controller is the interface module between EV and the mains power supply. It tells the EV what the maximum current is that the EV is allowed to draw. As the available current might fluctuate, the signal indicating this current can vary. It is a PWM sigal where the duty cycle encodes the current. Influence that can cause the current to vary are:
- Load balancing – Other EV Chargers requesting power;
- Smart Charging – other applicances consuming power or solar pannels providing power.
The Charge Controller also is responsble for disconnecting the EV from the mains when the EV is not requesting power. It does that by activating and deactivting the contactor.
Plug & Charge
Plug & Charge Charge controllers offer a very simple way of charging; there is no authentication. As soon as the user connects the EV to the EV Charger, the charging process will start. This is very conveniant for charging at private property. It might be less suitable for public charging as authentication is required for billing.
EV Chargers with sockets will still lock the plug in the EV Charger and secure the cable against theft. The way to unlock the plug is by disconnecting it from the EV. As by that, the pilot signal is lost, the Charge controller will release the lock.
While Plug & Charge don’t require authentication, an electronic key lock can be fitted to prevent unautorised users from connecting.