Charging, Managed Charging, and Grid-Services Models

For each charging event by each vehicle, V2G-Sim runs a charger sub-model that tracks a vehicle’s battery SOC and power transfer to/from the electricity grid on a second-by-second basis. The charger sub-model considers vehicle restrictions such as maximum power transfer rate, requirements for reduced charging rates as a battery approaches a full SOC, etc. The charger sub-model also considers charger restrictions, including the charger’s maximum power transfer rate (e.g. a vehicle capable of L2 charging plugged into an L1 charger will only charge at 1.44 kW). The charger sub-models are calibrated using experimental data for several different charger types using measurement data.

V2G-Sim also enables users to specify managed uni-directional or bi-directional charging control algorithms so that vehicles or chargers can respond to pricing signals or provide grid services. Users can create and execute their own managed charging or discharging models to predict the impact of their charging control algorithm on each individual vehicle or on any scale of the electricity grid (especially when coupling V2G-Sim with electricity grid models). A collection of sample managed charging and discharging control models are also included with V2G-Sim. Unique charging control algorithms can be applied to different vehicles within the collection of vehicles modeled within V2G-Sim.

Using these managed charging or discharging models the impacts from any vehicle-grid service can be modeled. Grid services in this context are broadly defined to include any distribution system, transmission system, or wholesale market objective that could be accomplished with modulated vehicle charging or discharging rates.  Examples of user-implementable control actions that may be taken to provide grid services in V2G-Sim are: 1) delayed charging, 2) modulated charging rates for grid services or charging price optimization, or 3) modulated bi-directional charging rates for grid services, etc.