this page should give a high-level overview of the features required for the caribou board to enable an electric vehicle to charge dc and ac current. (see also terms and standards)

hardware

general

the microcontroller on the board must be able to run java, as the intended open-source ISO 15118 stack rise-v2g is implemented in java.

power supply & wakeup

the board is powered by the 12V starter battery of the car. in idle mode the board must consume as little power as possible to not drain the 12V battery. it requires a wakeup logic which will detect when a plug is inserted and startup the system.

communication

vehicle side

communication to the VCU of the car via standard CAN 2.0.

interface to charging station

communication to the EVSE via powerline over the CP wire according to ISO 15118. to support on-board ac charging, the duty cycle of the CP line must be determined and resistors switched to communicate the vehicle status. additionally the PP wire must be evaluated to determine the maximum charging current allowed by the cable.

contactor control

right at the charging socket two contactors are placed which connect the dc link of the car to the socket for charging. the board must be able to drive both contactors and measure the auxiliary contacts to get feedback of the current contactor state (closed or open).

dc voltage measurement

the board must feature 2 isolated analog voltage measurements of the dc voltage. the dc voltage before and after the contactors is measured. only when the EVSE applies the voltage commanded by the car the contactors will be closed.

plug locking

the charging socket features a motor to lock the plug inside during charging. the board must drive this motor and read the feedback lines.

support on-board ac charging

the board supports an on-board ac charger which operates in AC mode 2 (only PP). the EVSE can regulate the allowed grid-side ac current by CP duty cycle. the board must offer a way to connect the PP wire to the on-board charger.

temperature measurement

a charge socket usually features two temperature resistors, one for dc and one for ac wire temperature. both temperatures must be evaluated.