power_supply_DC

Interface for power supplies used for DC charging

Implementation guidelines for this interface: 1) During start up of the driver, publish capabilities as soon as they are available, ideally in ready() function.

The charging logic in EvseManager will not allow any charging until it receives the capabilities at least once.

Capabilities may be published at any later point in time to update the values. This may happen if they e.g. change due

to thermal derating etc. If a charging session is active when the update is received,

only power/current limits will be applied immediately. All other values will become active at the next charging session.

2) setMode/setVoltageCurrent commands should be executed on the hardware immediately. If this is not possible because an error is currently active

(e.g. communication to the hardware is lost), the driver module shall cache the last mode and voltage/current settings.

Once the PSU is back on-line (e.g. after a CommunicationFault), set the last mode and voltage/current value received and only after that clear the error.

3) setMode to Off requires special attention. To avoid switching the output relays of the charger off under full load, make sure to return

from the setMode function(Off) only when the current is below a safe threshold for switching off the relays (exact value is hardware dependent).

If communication is lost with the power supply, make sure to still return, the call must not block for a longer period of time.

EVerest will ensure the order of the calls is correct during shutdown, but will not wait for the power supply to actually turn off:

1. call setMode(Off) on power_supply_DC

2. call allow_power_on(false) on evse_board_support

If the setMode(Off) returns immediately, it may happen that the bsp implementation opens the relays before the power supply is shutdown.

4) var voltage_current shall be published on regular intervals. The interval depends on the hardware, but it shall be at least once per second. If possible,

update at e.g. 4 Hertz is recommended.

Variables

voltage_current: object (power_supply_DC-VoltageCurrent)

Voltage/Current at the input/output

mode: string (power_supply_DC-Mode)

Current mode. Published on change.

capabilities: object (power_supply_DC-Capabilities)

Publish capabilities of this PSU.

Commands

setMode:void

Set operation mode of the bidirectional DC power supply

mode: string <required> (power_supply_DC-Mode)

Operation mode of power supply

phase: string <required> (power_supply_DC-ChargingPhase)

Charging phase for this mode change. This information should normally not be needed by the power supply, as it should always just operate in CCCV mode. Some special setups however are handling CableCheck/PreCharge/Charge a little bit different internally.

setExportVoltageCurrent:void

Set output target voltage limit. Must be within reported limits.

voltage: number <required>

Output voltage in Volt

current: number <required>

Output current limit in Ampere

setImportVoltageCurrent:void

Set minimal import voltage and current limit. Must be within reported limits.

voltage: number <required>

Current will be drawn if input is above this voltage (in Volt)

current: number <required>

Input current limit in Ampere

Errors

/errors/power_supply_DC :

CommunicationFault : The communication to the hardware or underlying driver is lost or has errors.

HardwareFault : The hardware reported a fault

OverTemperature : The hardware shut down because of over temperature. This should not be used if the power supply can handle temperature reduction by reducing output power, in this case update the capabilities as needed.

UnderTemperature : The hardware cannot operate because it is too cold

UnderVoltageAC : The AC input voltage is too low

OverVoltageAC : The AC input voltage is too high

UnderVoltageDC : The DC output voltage is too low

OverVoltageDC : The DC output voltage is too high

OverCurrentAC : The AC input current is too high

OverCurrentDC : The DC output current it too high

VendorError : Vendor specific error code. Will stop charging session.

VendorWarning : Vendor specific error code. Charging may continue.