🌞🔋 Off-Grid Power with MATLAB: 15 kW PV-Battery System Simulation
- lms editor
- Sep 12
- 3 min read
Reliable electricity in remote or isolated areas is possible with off-grid PV-battery systems. This blog explores a 15 kW off-grid PV battery simulation model developed in MATLAB, showcasing how solar power, advanced converters, and intelligent control strategies can ensure continuous standalone electricity supply.
☀️ System Overview
The simulated system is designed for off-grid applications, integrating solar PV, storage, and household loads.
⚡ PV Array: ~15 kW (26 panels in series × 3 parallel strings, each panel 193 W)
🔋 Battery Bank: 42 × 12 V batteries in series → 54 V, 200 Ah capacity
🔄 BU Converter: Handles step-down, MPPT, and bidirectional flow
🔌 Loads Supported: Both DC (LED, gate lights) and AC (appliances like refrigerators, fans, ACs, washing machines, pumps, TVs, etc.)
🔧 Circuit Breaker: Controlled by PV power and voltage thresholds for system safety
🌞 PV Array Design
Configured with 26 panels in series and 3 parallel strings.
Each panel: 193 W rating.
Total generation capacity: ≈ 15 kW at 1000 W/m² irradiance.
✅ Scalability & reliability make this array ideal for standalone power.
🔋 Battery Bank Configuration
42 × 12 V batteries connected in series.
Nominal system voltage: 54 V.
Capacity: 200 Ah.
Provides energy backup when solar power is insufficient.
🌙 Smoothly transitions between charging during the day and discharging at night or low irradiance.
🔄 Role of the Bidirectional (BU) Converter
The BU converter is the heart of the system:
⬇️ Steps down PV voltage (~750 V) → Battery voltage (54 V).
⚡ Implements Maximum Power Point Tracking (MPPT) for efficient energy capture.
🔄 Enables bidirectional flow: charging and discharging of the battery.
🎛 Controlled by a charger controller adjusting duty cycle based on real-time PV current & voltage.
🌀 Inverter Control for AC Loads
Converts DC battery power → AC for household appliances.
Uses ABC → DQ → ABC transformations for reference generation.
🎚 Proportional (P) controllers regulate inverter output.
Ensures:
✅ Sinusoidal waveforms
✅ Stable voltage supply
✅ Minimal distortion
This makes the system suitable for sensitive appliances like TVs, air conditioners, and refrigerators.
🔌 Load Management and Support
The system powers diverse loads:
💡 DC Loads: LED lighting, gate lights.
🏠 AC Loads: Washing machines, refrigerators, fans, air conditioners, TVs, pumps, and more.
📊 Real-time measurement blocks track AC & DC power usage to optimize operation.
This flexibility makes it perfect for rural electrification or standalone households.
🔧 Safety & Protection Mechanisms
A circuit breaker ensures safe operation.
Disconnection triggered when:
⚡ PV Power < 300 W
🔋 PV Voltage < 50 V
⛑️ Prevents battery over-discharge and system damage.
🌞 Real-Time Solar Irradiance Simulation
Simulates irradiance variations every 2 seconds.
Demonstrates how PV power fluctuates with sunlight availability.
Battery seamlessly transitions between charging & discharging modes.
🌀 Provides realistic insight into day-night cycles and cloud effects.
🔑 Key Takeaways
☀️ PV Array Design: Modular and scalable, optimized for 15 kW output.🔋 Battery Role: Balances supply-demand with smart charging/discharging.⚡ BU Converter: Critical for MPPT and bidirectional power flow.🌀 Advanced Inverter Control: Maintains high-quality AC power.🔌 Load Versatility: Supports both DC and household AC loads.🔧 Safety Features: Circuit breaker ensures operational reliability.🌞 Dynamic Simulation: Mimics real-world solar variability.
🎯 Conclusion
This 15 kW off-grid PV-battery system demonstrates how solar power, intelligent converters, and battery storage can provide reliable, standalone electricity without grid support.
Such systems are ideal for:
🌍 Remote villages
🏕️ Isolated communities
🏠 Residential solar independence
With integrated MPPT, battery management, and safety controls, the model proves that renewable energy can deliver sustainable and dependable electricity anywhere.
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