Configure an OCPP 2.1 CSMS to handle V2G bidirectional power transfer sessions using the BidirectionalChargingParameters functional block

Verified steps

1. Confirm both CSMS and charge point advertise and accept the 'BidirectionalCharging' functional block during the BootNotification / GetBaseReport exchange; the charge point must list it in its ReportedComponents.
2. When the EV connects and ISO 15118-20 BPT use-case is selected, the charge point sends a NotifyEVChargingNeeds request containing a V2XChargingNeeds object (not the older ChargingNeeds object used for unidirectional sessions); parse the fields including departureTime, evTargetEnergyRequest, evMaxDischargeEnergy, and evMaxDischargePower.
3. Respond with a SetChargingProfile request that includes a ChargingProfile with purpose 'TxDefaultProfile' and a ChargingSchedule whose chargingRateUnit is 'W'; negative power values in chargingSchedulePeriod entries signal discharge (export) — confirm the charge point firmware supports negative limits before sending.
4. Monitor ongoing sessions via MeterValues notifications; the measurand 'Power.Active.Import' will report negative values during discharge intervals, and 'Energy.Active.Export.Register' tracks cumulative export energy.
5. Send ClearChargingProfile or a new SetChargingProfile to adjust the discharge schedule in response to grid signals or market price changes during the session.
6. Handle session termination: on StopTransaction (OCPP 2.0.1 terminology) or TransactionEvent with eventType 'Ended', reconcile energy import and export values separately for billing and settlement.