Principle of selection of photovoltaic inverter

Photovoltaic inverter is the main component and an important part of photovoltaic power generation system. In order to ensure the normal operation of photovoltaic power generation system, the configuration and selection of photovoltaic inverter is more important.The configuration of photovoltaic inverter should be determined according to the technical indicators of the whole photovoltaic power generation system and refer to the product manual provided by the manufacturer, but also focus on the following technical indicators.

1. Rated output power

Rated output power indicates the capacity of the PHOTOVOLTAIC inverter to supply power to the load.Photovoltaic inverters with high rated output power can drive more loads. When selecting photovoltaic inverters, sufficient rated power should be considered first to meet the requirements of the equipment for electrical power under the maximum load, as well as the expansion of the system and the access of some temporary loads.When the electrical equipment mainly adopts pure resistive load or the power factor is greater than 0.9, the rated output power of the photovoltaic inverter is generally 10%-15% higher than the total power of the electrical equipment.

2, output voltage adjustment performance

The output voltage adjustment performance represents the voltage stabilizing capacity of the output voltage of the photovoltaic inverter.General photovoltaic inverter products are given when the DC input voltage fluctuates within the allowable fluctuation range, the percentage of fluctuation deviation of the output voltage of the photovoltaic inverter, usually called voltage adjustment ratio.High-performance photovoltaic inverters should also give the percentage deviation of the output voltage of the photovoltaic inverter when the load changes from zero to 100%, which is usually called the load adjustment rate.The voltage adjustment rate of the photovoltaic inverter with excellent performance should be less than or equal to ±3%, and the load adjustment rate should be less than or equal to ±6%.

3. Efficiency of the machine

The efficiency of the whole system represents the power loss of the photovoltaic inverter.The efficiency value of the photovoltaic inverter with large capacity should also be given under full load and low load. Generally, the efficiency of the inverter below KW level should be 80%-85%.The efficiency of the 10KW class should be 85%-90%;The efficiency of larger power must be above 90-95%.The efficiency of the inverter has an important impact on the photovoltaic power generation system to improve the effective power generation and reduce the cost of power generation, so the photovoltaic inverter should be compared as far as possible, and the product with higher efficiency of the whole machine should be selected.

4. Startup performance

Photovoltaic inverters should be guaranteed to start reliably under rated load.High-performance photovoltaic inverters can start at full load for many times without damaging power switching devices and other circuits.For their own safety, small inverters sometimes adopt soft start or current limiting start measures.