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Chuck edited this page Nov 18, 2018 · 4 revisions

SteVe-smartcharge wiki

This fork of SteVe supports development of OCPP smart charging use cases.

The initial focus is on local smart charging intended for "load management" under OCPP1.6J. A conceptual example of this topology is given in the OCPP1.6 specification section 3.13:

In this initial use case SteVe will be a component of the Local Controller.

In this architecture, a separate software component, the load manager, is responsible for smart charging "business logic". Its interface to SteVe comprises two primary functions:

  1. The ability for the load manager to read per-vehicle current consumption on a real-time basis (several times per minute)
  2. The ability for the load manager to set per-vehicle "offered current" (J1772 pilot signal value)

In addition, these secondary capabilities are useful:

  1. The ability for the load manager to read per-vehicle offered current (as a confirmation of its setting)
  2. The ability for the load manager to set and confirm default offered current settings which will apply within the charging station during fault conditions (e.g. loss of communication, power failure at Local Controller)

It should be noted that this architecture does not exactly match the example scenario of the OCPP1.6 specification, in that the Local Controller is more self-contained:

  1. it offers direct web-based UI
  2. it does not rely on a separate Central System to provide ChargePointMax profiles
  3. it manages authentication and logging locally

The "business logic" of this load management program deals with an installation in which the electrical feeder circuit capacity is insufficient to operate all charge points simultaneously at full power. Its responsibility is to allocate available current to the connected vehicles in such a way that no circuit is overloaded. There are many factors that could contribute to optimal allocation, if they are known. For example, the vehicle state of charge, expected departure time, maximum charge rate capability, customer priority, and non-EV power usage on shared electrical feeders could be considered. To this end, the load management program maintains a configuration database including some table data that should be synchronized with Steve.

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