Correct selection of photovoltaic inverter


In order to correctly select the inverter for photovoltaic power generation system, we should pay attention to the following requirements:

1. Rated output capacity

The inverter with high rated output capacity can carry more electric loads, but when the load of the inverter is not pure resistive, that is, when the output power is less than 1, the load capacity of the inverter will be less than the rated output capacity.

2. Output voltage stability

Battery is used as energy storage equipment in off grid photovoltaic power generation system. When the battery with nominal voltage of 12V is in floating charge state, the terminal voltage can reach 13.5V, and the short-time overcharge state can reach 15V. When the battery is discharged with load, the terminal voltage can drop to 10.5V or lower, and the fluctuation of the terminal voltage of the battery can reach about 30% of the nominal voltage, This requires the inverter to have good voltage regulation performance, in order to ensure the photovoltaic power generation system to supply power with stable AC voltage.

3. Overall efficiency

Under normal circumstances, the efficiency of the inverter below kW level should be 80% - 85%, and the efficiency of the inverter below 10kW level should be 85% - 90%. The efficiency of the inverter has an important impact on improving the effective power generation and reducing the power generation cost of the photovoltaic power generation system.

4. Protection function

Over voltage, over current and short circuit protection are the most basic measures to ensure the safe operation of the inverter. The sine wave inverter with perfect function also has the functions of under voltage protection, phase loss protection and over temperature alarm.

5. Starting performance

The inverter should be able to start reliably under the rated load. The high-performance inverter can start continuously at full load for many times without damaging the power devices. For its own safety, the small inverter sometimes adopts soft start or current limiting start.