EV Charging Station

EV Charging Station#

EV charging stations in POLARIS are agent-based entities that manage the physical charging infrastructure. Each station tracks plug availability, vehicle queuing, charging progress, pricing, and optional vehicle servicing (e.g., cleaning for TNC fleets).

The figure below illustrates the lifecycle of a vehicle through the charging station — from arrival and queuing through the charging process to departure and record output.

Charging Station Lifecycle

Station Properties#

Each charging station is defined by:

  • Location: An activity location and zone in the supply database.

  • Plug types: A list of charger types (e.g., Level 2, DC Fast Charging) available at the station, each with:

    • Plug count (total number of plugs of that type),

    • Charge rate (kW or miles per minute),

    • Unit price ($/kWh).

  • Power sources: Fuel type of the electricity source (e.g., grid, solar).

  • Station type: Categorization such as public, workplace, residential, or fleet depot.

  • Service bays (optional): Number of bays for vehicle servicing (cleaning, maintenance), with configurable service and cleaning durations.

Charging Process#

  1. Arrival and queuing: A vehicle arrives at the station and is added to the charging queue. If a compatible plug is available, charging begins immediately. Otherwise, the vehicle waits up to a configurable maximum wait time.

  2. Plug assignment: When a plug becomes available, the station assigns it to the next queued vehicle based on arrival order.

  3. Charging update: The station periodically updates each vehicle’s battery level based on the plug’s charge rate and the elapsed time, accumulating the charging cost at each update.

  4. Departure: Charging ends when the vehicle’s target SoC is reached or when a departure time constraint is met. The vehicle is removed from the queue and the plug is released.

Charging Records#

Each completed session produces a charging record containing:

Field

Description

Station ID

Identifier of the charging station

Vehicle / Person

The vehicle and (if applicable) person associated with the session

Charging Fleet Type

Personal, TNC, or freight

Time In / Start / Out

Arrival, charging start, and departure times

Energy In / Out (Wh)

Battery energy at arrival and departure

Battery In / Out

State-of-charge (fraction) at arrival and departure

Charged Money ($)

Total cost of the charging session

Miles In / Out

Odometer readings at arrival and departure

These records are written to the output database for post-simulation analysis of station utilization, energy throughput, and revenue.

TNC Vehicle Servicing#

Stations may also provide servicing for TNC fleet vehicles (e.g., interior cleaning between passenger trips). A separate servicing record logs each event with the station ID, vehicle, location, and service times. Service bays operate independently of charging plugs.

References#