Single Stage Grid Connected Solar PV Battery System
System Configuration
The system components include:
Grid System: Rated at 154 MW, with a step-down transformer converting to 380 volts.
Loads: Two loads rated at 2 kW and 1.5 kW respectively.
Batteries: 40 batteries in series, each with a rating of 5.4 kWh.
Solar PV System: Maximum power output of 15 kW, connected to the DC link along with batteries.
Simulink Model Overview
The Simulink model is structured as follows:
Solar PV and Battery Integration: Both are connected to the DC link capacitor.
Inverter and Transformer: Includes a neutral-point-clamped inverter, LC filter, and step-up transformer to match grid voltage (380V).
Control Logic for Inverter
MPPT (Maximum Power Point Tracking):
Uses PV voltage and current to track changes in power and adjust reference voltages accordingly.
Reference voltages are compared with DC link voltage to regulate inverter operations.
Current Control:
Generates direct axis current reference based on regulated voltage.
Utilizes a decoupling concept for precise current control.
Voltage Conversion and Modulation:
Converts three-phase quantities to two-phase (dq) for effective control.
Generates modulation signals for the inverter to control power flow.
Simulation and Results
Performance under Various Irradiance Levels:
1000 W/m² Irradiance:
Solar PV supplies 14.52 kW, with excess power sent to the grid.
Battery assists in load support, maintaining system stability.
500 W/m² Irradiance:
PV output reduces to 7.2 kW, battery starts charging mode.
System continues to supply loads and feed surplus power to the grid.
300 W/m² Irradiance:
PV output further decreases to 4.28 kW.
Battery charges more actively, grid interaction remains stable.
200 W/m² Irradiance:
PV output drops to 2.8 kW.
Battery and grid share load supply, ensuring continuous power delivery.
Conclusion
The single stage grid-connected solar PV battery system demonstrates robust performance across varying irradiance conditions. By effectively managing power generation, storage, and grid interaction, the system optimizes energy efficiency and ensures reliable operation.
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