🔋⚡ Grid Connected PV Battery with Non-Linear Load in MATLAB – Complete Guide

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3 hours ago
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In the era of renewable energy integration, efficient PV–battery–grid systems are essential for sustainable and uninterrupted power supply. This post walks you through the design, control, and simulation of a grid-connected PV battery system with a non-linear load in MATLAB/Simulink.

☀️ 1. PV System Overview

The system starts with a 4.6 kW solar PV array rated at 29.5 V and a peak current of ~164 A.

Boost converter with Perturb & Observe (P&O) MPPT algorithm ensures maximum power extraction.
Real-time measurement of PV voltage, current, and power allows precise control.

🔋 2. Battery Integration

A 240 V battery with an initial State of Charge (SOC) of 50% is connected via a DC–DC bidirectional converter.

Controlled by PI controllers to regulate charging and discharging.
Maintains DC-link voltage stability and supports power balancing between PV, load, and grid.

🌀 3. Inverter and Grid Connection

The single-phase inverter connects to a 220 V AC grid through an L-C filter.

Grid voltage and current are measured at the Point of Common Coupling (PCC).
The system supports constant power mode when load demand is below a threshold.

📉 4. Non-Linear Load Simulation

Three types of loads are simulated:

Base load – always connected.
Additional loads – switched at specific times (after 5 s and between 6–7 s) to test dynamic performance.
Load current transformation (αβ → DQ) enables accurate control.

🔄 5. Control Logic

Switch-case compares load power (PL) to a threshold (1,500 W).
If PL > 1,500 W → reference current is set.
If PL ≤ 1,500 W → grid operates in constant power mode.

📊 6. Simulation Results

Initial stage (0–2 s): PV ~1,200 W, grid supplies deficit, battery idle.
3 s onwards: PV rises to ~2,400 W, battery starts charging.
4 s peak: PV ~4,600 W, battery continues charging, grid exports power.
After 5 s: Load drops below threshold, grid power remains constant despite load variation.
Irradiance change (300 → 700 → 1,000 W/m²) increases PV current accordingly.

🌍 Benefits of This System

✅ Stable DC-link voltage for inverter operation✅ Smart power sharing between PV, battery, and grid✅ Uninterrupted power supply even with variable loads✅ Efficient battery charging strategy✅ Improved grid stability under varying irradiance and load

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Grid connected PV system, MATLAB Simulink PV model, Solar PV battery integration, Non-linear load simulation, MPPT boost converter, Grid-tie inverter, Renewable energy modeling, PV battery grid MATLAB, Power flow control, Constant power mode grid