Smart Charging (V1G)

In a V1G architecture, electrical energy flows exclusively from the grid to the vehicle. Unlike Vehicle-to-Grid (V2G) systems, the on-board charger or Electric Vehicle Supply Equipment (EVSE) does not contain an inverter capable of exporting power. This simplifies the hardware to a standard rectifier, reducing cost and eliminating the need for complex anti-islanding protection. The vehicle acts purely as a controllable load, not a distributed energy resource.

The defining mechanism of V1G is the dynamic adjustment of the charging rate by an external entity, typically a Charge Point Operator (CPO) or utility. This is achieved by modulating the PWM (Pulse Width Modulation) signal on the control pilot pin of the connector, per IEC 61851-1. The EVSE continuously varies the maximum allowable current, commanding the on-board charger to ramp up, throttle down, or pause charging in real-time without any physical disconnection.

V1G is primarily deployed to solve local infrastructure constraints. Algorithms enforce transformer load management by aggregating EV loads and ensuring the total demand never exceeds the thermal rating of the distribution transformer. Key applications include:

• Peak shaving: Reducing demand during the utility's peak pricing window.
• Dynamic load balancing: Allocating limited site capacity across multiple charging stalls.
• Demand charge management: Capping instantaneous power to avoid commercial tariff penalties.

V1G functionality is implemented across multiple communication standards. Basic control uses the physical PWM signal, while advanced scheduling uses high-level protocols. Open Charge Point Protocol (OCPP) allows a central management system to send smart charging profiles to stations. OpenADR enables utilities to broadcast demand response events. ISO 15118 enables digital scheduling via high-level communication over the control pilot, allowing the vehicle to negotiate a charging schedule based on energy contracts.

Advanced V1G implementations use Model Predictive Control (MPC) to solve the optimal charging schedule. The controller uses forecasts of energy prices, building load, and solar generation to minimize a cost function over a receding horizon. The optimization often uses Mixed-Integer Linear Programming (MILP) to handle discrete charging states while respecting battery constraints like State of Charge (SoC) limits and maximum C-Rate. The result is a time-series power profile that minimizes cost while ensuring the vehicle reaches the target SoC by the departure time.

Unlike uncontrolled charging, V1G algorithms can integrate battery degradation models to extend asset life. By avoiding high C-Rates at extreme State of Charge (SoC) levels and minimizing time spent at high voltage, the system reduces calendar aging and lithium plating. The optimization balances grid cost savings against the marginal cost of capacity fade, ensuring that aggressive load shifting does not inadvertently damage the vehicle's State of Health (SoH).

An international standard defining the Vehicle-to-Grid Communication Interface (V2G CI). While essential for bidirectional V2G, it also specifies high-level communication for V1G via Power Line Communication (PLC).

• Enables Plug & Charge authentication using digital certificates
• Allows the vehicle to communicate its State of Charge (SoC) and charging schedule
• Mandates TLS encryption for secure data exchange

An advanced process control algorithm that solves a finite-horizon optimization problem at each time step. In V1G, MPC uses forecasts of energy prices and building load to determine the optimal charging rate trajectory.

• Minimizes cost while respecting grid constraints
• Handles Multi-Input Multi-Output (MIMO) systems
• Anticipates future events rather than reacting to current errors

A real-time power allocation algorithm that distributes available electrical capacity across multiple charging points. DLB is the local, on-site enforcement mechanism that prevents a V1G schedule from tripping the main circuit breaker.

• Monitors total building consumption vs. capacity
• Dynamically adjusts per-charger current limits
• Prevents costly infrastructure upgrades by managing after-diversity maximum demand

The bidirectional evolution of V1G. While V1G only modulates charging rate, V2G enables the vehicle to discharge stored energy back to the grid. V1G is often the regulatory and technical prerequisite for V2G deployment.

• Provides frequency regulation and spinning reserves
• Requires a bidirectional charger and utility interconnection agreement
• Accelerates battery degradation if not managed by sophisticated algorithms