Overall System Description
The illustrated system represents a standalone (off-grid) solar PV configuration designed to generate, store, and supply electrical power independently of the utility grid. The architecture ensures reliable energy availability through controlled battery charging, safe DC distribution, and stable AC/DC power delivery to connected loads.
1. PV Array – DC Power Generation
The PV array converts solar irradiance into direct current (DC) electricity.
- Modules are electrically interconnected to achieve the required system voltage.
- Input-side protection includes DC fuses and Surge Protection Devices (SPDs) to safeguard against short circuits and lightning-induced transients.
- Generated DC power is routed directly to the charge controller for regulation.
2. Charge Controller (MPPT / PWM)
The charge controller regulates power flow between the PV array and the battery bank.
- MPPT (Maximum Power Point Tracking) optimizes energy harvest by continuously adjusting operating voltage.
- Prevents battery overcharging and deep discharge, extending battery life.
- Maintains system voltage stability under varying irradiance conditions.
3. Battery Bank – Energy Storage
The battery bank stores excess solar energy for use during night-time or low-sun periods.
- Configured in series/parallel to match system voltage (e.g., 12V / 24V / 48V DC).
- Protected by DC fuses and isolators to ensure safe operation and maintenance.
- Acts as the backbone of system reliability in off-grid applications.
4. DC Protection & Distribution
Before power enters the inverter, the DC circuit includes:
- DC fuses and MCBs for overcurrent protection.
- DC SPDs to protect sensitive inverter electronics.
- Clearly defined DC input isolation for safe servicing.
5. Off-Grid Inverter (DC–AC Conversion)
The off-grid inverter converts stored DC energy into 230V AC power.
- Provides a pure sine wave output, suitable for residential and sensitive electronic loads.
- Includes an automatic transfer switch (optional hybrid mode) to prioritize solar/battery power.
- Built-in surge protection enhances system durability.
6. AC and DC Load Supply
The system supports both AC and DC loads:
- AC Loads (230V AC): Lighting, appliances, household equipment.
- DC Loads (12V / 24V DC): LED lighting, DC fans, low-power devices (optional).
This dual-load capability improves overall system efficiency by reducing unnecessary conversion losses.
7. Key Advantages of the System
- Complete independence from the utility grid
- Reliable power availability through energy storage
- Enhanced safety through layered electrical protection
- Optimized solar utilization via MPPT technology