Documentation

Dynamic load management

Our dynamic load management is used when the house connection cannot provide sufficient power for the existing wallboxes.

Thanks to the cFos Charging Manager, several wallboxes can be operated simultaneously without overloading the house connection. Thanks to the unique dynamic load management, the cFos Charging Manager is able to distribute the maximum available connected load in the building to the electric cars to be charged. In addition, the existing wallboxes can be prioritised differently so that the available charging power is initially distributed to higher-priority wallboxes. In addition to our own wallboxes, wallboxes from other manufacturers can also be integrated into the load management system.

The house connection is normally designed for the use of the building (e.g. residential, offices, etc.). In many cases, however, the available power is not fully utilised so that it can be used to charge electric cars. The cFos Charging Manager can measure the building's current power requirements by querying meters and dynamically adjust the available charging power.

It is also possible to take into account the consumption of heat pumps and ventilation systems as well as the generation capacity of solar systems in load management. The cFos Charging Manager can even provide only the unused surplus of your PV system as charging power.

The Charging Manager algorithm

The cFos Charging Manager performs the following actions every three seconds:

  • Readout of all meters, wallboxes, inverters and other devices. Here, the cFos Charging Manager parallelises the device accesses.
  • Check whether charging is permitted at all (authorisation). The Charging Manager can check this using its own user administration or an external OCPP backend can decide this.
  • Calculate maximum available charging current, generation current, solar surplus, etc.
  • Distribution: All wallboxes can be prioritised and, if necessary, grouped together in charging groups, which also have a priority. Charging groups can in turn be summarised in charging groups.
  • Distribution: The available charging current or charging power (in the event of a PV surplus) is distributed to the charging cars according to the prioritisation. Various charging rules and other limitations can be taken into account here, including specifications from an external OCPP backend. Other features: charging budgets, time budgets, first come first served, interactive overrides by the user, etc.
  • If there is not enough power available, cars can be paused and then loaded using the round robin method.
  • Checking and processing of automatic switching between 1-phase and 3-phase.
  • The distribution first takes place for all wallboxes that want to charge excess power. Then for all "normal" charging cars. Surplus charging and normal charging can also be combined.
  • Checking and correction of phase shift load.
  • Updating of any existing external OCPP backends. The cFos Charging Manager can also connect wallboxes that are not capable of OCPP to an external backend.
  • Recording of transactions.
  • Save and/or transmit signed meter readings if necessary.
  • Calculation of all user-defined variables and formulas.
  • Evaluation of charging rules for battery storage.
  • Determination of the status of all user-defined outputs, e.g. switching contacts.
  • Transmission of all values to wallboxes, battery storage systems, heat pumps, etc. The cFos Charging Manager parallelises all device accesses.

Alternatively, the Charging Manager can also work in "monitoring mode", i.e. it only reads values and does not intervene in a controlling capacity. It then serves as a connectivity engine for the range of devices we support. Meters, inverters and battery storage systems can be integrated into the Charging Manager without changing the programme using reloadable meter definitions (which users can also create). For wallboxes that do not speak OCPP, small "drivers" are required, which can be created by cFos eMobility.

Charging Manager instances can also be cascaded, i.e. a load manager controls further Charging Managers, e.g. in a multi-storey car park.

Furthermore, the actual charging currents can also be specified externally via HTTP (keyword "charging plans"). This allows an external "optimiser" to be connected, which controls all current flows between the devices.