PV based EV charging with V2G and G2V Operation
In today's discussion, we explore a model developed for solar PV-based electrical charging coupled with Vehicle-to-Grid (V2G) technology under the Grid to Wheels (GTW) concept.
The model comprises the main grid with a rating of 124 megawatts at 34.5 kilovolts, stepping down to 400 volts. An Electric Vehicle (EV) battery is connected to the solar PV grid via a bidirectional DC-DC converter with a voltage controller. The DC link voltage is compared to a reference voltage, maintaining it around 470 volts. A Proportional-Integral (PI) controller processes the comparison result, generating pulses for the bidirectional DC-DC converter.
The EV battery charging strategy involves three modes of operation:
Mode 1 (PV Power Charging): During daytime when PV power is available and the battery state of charge (SOC) is below 95%, the power generated charges the EV battery.
Mode 2 (V2G Concept): The EV battery supplies power to the grid in V2G mode, sending excess power when the SOC is above 95%.
Mode 3 (Grid to Vehicle): The EV battery is charged from the grid when required.
Solar PV System:
The solar PV system includes panels connected in series and parallel, using a boost converter with Maximum Power Point Tracking (MPPT) for optimal power extraction.
A feed-forward decoupling control concept is employed for the inverter. Grid voltage and current are transformed to DQ form, and the model features an MPPT algorithm for efficient power extraction.
Mode Transition Logic:
The model includes logic for transitioning between modes based on SOC levels, power availability, and user-defined settings. Mode transitions occur seamlessly, adapting the system to optimal charging or discharging states.
Simulation results showcase the model's performance under different scenarios, including variations in solar radiation, SOC levels, and power management strategies. The system demonstrates effective operation, efficiently managing power flow between the solar PV, EV battery, and the grid.
The developed model illustrates a comprehensive approach to solar PV-based electrical charging with dynamic modes for optimal power utilization. The integration of V2G technology under the GTW concept offers flexibility and efficiency in managing power resources. The simulation results confirm the model's effectiveness in real-world scenarios.